I guess we'll never know the answer to this question.

[Tigermegatron]

I guess we'll never know the answer to this question. "Why the generation one USA Hasbro TF cartoon series got cancelled by Hasbro"?
Because all these decades Hasbro & Takara consider this a privacy matter that buyers/fans have ZERO rights to know.

Below is some invalid & Valid fans speculations

Invalid speculation #1,TF toys were selling badly thus was the reason the TF cartoon series got cancelled by Hasbro. This just seems incorrect as the 1984,1985,1986 & 1987 TF toys all had strong sales,to the extent it was super hard to find about 30% of the toys in stores each year.

Invalid speculation #2,Changing time slots & bad time slots were due to the viewers not liking the newer seasons,which is why hasbro cancelled the TF cartoon series. This just SEEMS WRONG,As the newer episodes always aired in the best weekly afternoon time slots. when their were no newer episodes,extremely long Hiatus breaks of extreme re-runs would result in the Re-runs being aired in the morining time slots from 6:30 am or 7:00 amm,these time slots were not death time slots,as kids watched in the morning as they were getting ready for school. When their was newer episodes,the time slots always changed back to the weekly afternoon time slots.

Invalid speculation #3,Extremely long Hiatus breaks which resulted in extreme re-runs was the reason hasbro cancelled the TF cartoon series. on-line fans speculated that viewers lost interest & moved on to other stuff. THIS I GOTTA DIS-AGREE WITH,because everytime a newer season aired,old viewers returned,tons od newer viewers arrived. Each newer season got decent rattings & were put back into the afternoon weekly time slots. even season 4 which only had a few episodes got decent rattings.

VALID Speculation #4,Wally burr & the Voice overs strike that happened in the 1980's was one of the key factors that led Hasbro to cancel the TF cartoon series. THIS IS GOTTA AGREE/DISAGREE WITH 50/50. It's possible the TF voice overs actors were fed up with wally burr & refused to further work with the man. Wally burr was named by the voice overs actors strike committee as being a negative influence in his field. After that voice overs actors strike it's possible Hasbro didn't want to meet the demands of the newer contracts laws set by the voice overs actors unions.

The disagree part comes from the Fact that Hasbro could have easily chosen to introduce newer TF characters in season 4,get rid of the older characters,thus hire newer voice overs actors from Canada. Viewers couldn't complain due to the newer TF characters needing newer voices. Hasbro would have never had the seasons 1,2 & 3 TF characters voiced by newer canadian voice actors,this was never on the table for discussion. Hasbro would have introduced newer toys,newer cartoon characters,newer canadian voice overs actors at a cheap rate with zero USA union laws in place.

Valid Speculation #5,Sunbow the TF animation studio went belly up. G.I Joe had their newer cartoons animated by DIC. It's possible DIC was not up to the standards hasbro wanted to Animate Transformers robots. It's possible DIC wanted too much money to animated the TF cartoon series & was trying to charge leaps & bounds more than Sunbow. It's possible Takara liked working with Sunbow but didn't like DIC perhaps due to price,inferior animation,slowness,perhaps DIC animating too much of Takara's Competition.

Valid speculations #6,Creative differences/visions for the future TF cartoons by Hasbro & Takara. Caused Hasbro to Cancel the TF cartoons series while Takara continued creating newer TF G-1 cartoons series like Headmasters,Masterforce,Victory. THIS ONE AT LEAT HAS MERIT. As takara didn't like the nebulans idea & didn't use it in their Headmasters cartoon series.

I think at one point Hasbro might have been seriously considering dubbing the headmasters,masterforce & victory series & airing them in America. I think time was a factor as time went by too fast,hasbro dragged their feet too long,after a while it was too late as newer toys in stores didn't match the characters in the cartoons anymore. Season 5 Puppet PMOP hinted to Tommy that he would return,this was a hint hasbro was seriously considering dubbing the masterforce series for the USA. Hasbro probably nixed the idea probably due to the characters,animation & violence being so radically different to previous TF cartoons from the USA. It's possible takara didn't want to share these exclusive G-1 cartoons series with Hasbro,Wanted to be compensated by hasbro,The newer animations studios didn't want to lease their stuff to hasbro to dub in america,etc...

Invalid speculation #7,Hasbro never planned for the TF G-1 toy line & cartoon series to last this long. Thus they were caught off guard & not fully prepared to keep creating newer TF cartoon season or series. This I gotta disagree with,as the G.I Joe toy line & cartoon series lasted well into the early 1990's. So clearly Hasbro was prepared at one point to keep releasing newer TF cartoons seasons & newer TF toys. the sheer fact that the TF USA G-1 toy line ended in 1990 Debunks this speculation.

Invalid speculation #8,Hasbro only ever planned to create a certain numbers of TF G-1 episodes. Hasbro Was confident that re-runs would sell newer 1988,1989,1990 TF USA toys. This I gotta disagree with,as the key factor for the 1988,1989 & 1990 TF G-1 toy sales being so bad was due to the cancellation of the G-1 cartoon series. Hasbro knew well in advance the cartoons were a 22 minute long commericial that advertised the toys. Hasbro knew well in advance without newer cartoons,the toys would sell at a slower pace in stores. CLEARLY OTHER KEY FACTORS WERE THE REASONS.

[Onslaught Six]

The answer's obvious--the movie flopped (financially speaking) and they were running out of ideas. Season 3 wasn't well received, and it was cheaper to re-air old episodes with a framing device (Tommy Kennedy and a big puppet) than it was to create new animation. That's all.

[Tigermegatron]

The answer's obvious--the movie flopped (financially speaking)

Hasbro is in it for the toys,they could care less if the media fails. The media is a tool to help sell the toys.

The 1986 TF Animated movie wasn't that exspensive to create. Even though the movie did bad in movie theatre sales,I suspect,at the very least the movie theatre sales made hasbro back the money they spent to create the movie. The VHS sales also helped make back some money that it cost hasbro to create the movie.

Season 3 wasn't well received .

This is a heated on-line debate,some agree,some don't agree. so I won't touch this one with a Ten foot pole.

The 1986 & 1987 TF toys sold beyond well in stores,That's all that Hasbro cares about,as the bulk of their profits come from the toys they sell in stores.

and they were running out of ideas

I disagree with this,As Hasbro's crew was really on the ball with all their creative ideas from 1986,1987,1988,1989 & 1990. Just to name a few ideas had: Futeristic time line,planet nebulan,quintessons,junkions, alt modes,headmasters,targetmasters, powermasters, pretenders,action masters,trottlebots,horrorcons,combiners,city formers & the list goes on.

and it was cheaper to re-air old episodes with a framing device (Tommy Kennedy and a big puppet) than it was to create new animation. That's all.

Clearly this was not intendened. Hasbro knew well in advance that without the newer cartoons,the newer TF toys sales would plummet in sales. The old cartoons only advertised the 1984-1987 TF toys. kids didn't buy the 1988,1989 & 1990' TF toys in great supply because the cartoons weren't their to give them fleshed out persona's & advertise them for 22 minutes per episode.

Something else happened behind the scenes. like the 1980's voice overs actors strike. Wally burr the TF voice director being named as a negative entity by the voice overs actors unions,sunbow closing down. Takara & Hasbro having different creative visions for the cartoons/toy lines in 1987 thru 1990.

G.I Joe in 1987 had lower toy sales & lower cartoon viewership rattings compared to Transformers,yet was successful at going with DIC to create newer G.I Joe cartoons.

It's possible since Hasbro didn't own TF but were liscensing it from Takara,Hasbro was unable to contact DIC & have them create newer TF cartoons. Takara might have needed to be involved & maybe said no to DIC or another Animation studio Hasbro was interested in at the time for Transformers.

Season 5 PMOP puppet prime kept hinting to Tommy Kennedy that he was returning in a big way. Clearly these hints were hinting at hasbro creating newer TF cartoons or Hasbro dubbing into engish the takara headmasters,masterforce & victory cartoons. Both routes probably failed for Hasbro.

[Shockwave]

Hasbro is in it for the toys,they could care less if the media fails.

Hasbro knew well in advance that without the newer cartoons,the newer TF toys sales would plummet in sales.

So which is it? Does Hasbro not care about media, cause if they're in it just for the toys and the toy sales will plummet without media then the two statements are contradictory.

[Sparky Prime]

Hasbro is in it for the toys,they could care less if the media fails. The media is a tool to help sell the toys.

Hasbro certainly would care if the media failed. If people don't like the show, then what are the chances they will be all that interested in the toyline, and as a result, that the toys will sell all that well? And how would they promote the toys with out the show? How well a show does can have a direct impact on a toyline, and vise versa. Besides, Hasbro has taken a very active interest in their media. Why do you think in recent years Hasbro partnered with the Discovery Channel to create the HUB network?

The 1986 & 1987 TF toys sold beyond well in stores,That's all that Hasbro cares about,as the bulk of their profits come from the toys they sell in stores.

The popularity of the line in North America began to decline around that time though, especially when show came to an end in 1987.

It's possible since Hasbro didn't own TF but were liscensing it from Takara,Hasbro was unable to contact DIC & have them create newer TF cartoons. Takara might have needed to be involved & maybe said no to DIC or another Animation studio Hasbro was interested in at the time for Transformers.

Um... Transformers has always been owned by both Hasbro and Takara as part of a joint venture between the two companies from the franchise's conception. And there was newer Transformers episodes that Takara produced for Japan in the form of Headmasters, despite Hasbro deciding to end the G1 cartoon with "Rebirth", which was actually produced separately for Hasbro in order to wrap up the series for North America.