Looper, seemingly independently of the actor in question, report that Disney's flop John Carter ruined star Taylor Kitsch's then blooming career.

Probaby an accurate claim.

Films are the culmination of often years of planning, writing, filming and post production but viewers only see the actors and tend to associate excellence or lack thereof with them, the franchise or maybe studio.

Stars of flops often fade away into obscurity.

The article implies that John Carter's performance wasn't a reflection of its quality but rather "poor marketing or disinterest in the premise".

Really?

Carter was panned by critics and just one in a very long line of unsuccessful Disney forays into sci-fi.

Indeed, Disney may even have been aware of the curse - it deleted the words "Of Mars" from John Carter's original title, fearing it was box office poison.

Possibly it was judged to a higher standard than other sci-fi films of the day or predceding it, but it begged that because it was so very obviously trying to be an epic of Star Wars proportions. John Carter didn't deliver.

Its special effects were also very obviously expensive. Seeing that, viewers reasonably expected the rest of the film to live up to that standard. John Carter didn't deliver.

If audiences indeed are more forgiving of it today it could be courtesy of more exposure to mediocre sci-fi.

Plus there's the pandemic.

Trapped indoors for extended periods it's possible that people will end up watching all sorts of things they otherwise wouldn't.

References

Crockford, C. M. (October 4, 2021). The Action-Adventure Movie That Ruined Taylor Kitsch's Career. Looper.

Lambie, Ryan (June 26, 2019). Exploring Disney’s Fascinating Dark Phase of the 70s and 80s. Den of Geek.

Saunders, Emma (March 20, 2021). A brief history of big screen flops. BBC.