Technically, Star Wars had TWO underperforming movies (Last Jedi also was a bomb ESPECIALLY in China, pretty much the one audience that exceeds America at the moment in Hollywood’s view. And to add insult to injury, based on how JJ Abrams behaved where he effectively pulled the same stunt that the infamous 2016 remake of the Ghostbusters pulled by inferring its audience was “afraid of women” suggests even HE knew it was a bust in America as well). And apparently Star Wars Resistance got pretty bad reviews from what I heard. In fact, it’s not just the movies, even the actual merchandising for Star Wars has been bombing lately, having a massive decrease in revenue (and if that’s not bad enough, apparently it’s bad enough to actually affect the mainline Disney products like Frozen): https://www.oneangrygamer.net/2019/01/star-wars-revenue-takes-hit-across-video-games-merchandise-comic-books/75132/ In fact, Disney’s doing so badly in terms of sales that, at the time that article was written, the MCU is pretty much the only thing keeping Disney afloat, and based on Captain Marvel’s current reception, I’d argue it’s probably not even going to have that keeping it aloft any longer. I’m guessing Iger’s probably going to need to consider resigning if he doesn’t want the shareholders to give him the same fate that Michael Eisner got (being ousted, in other words).
Also, the first Captain America movie was not made by Disney (heck, it predated the deal selling the MCU over to Disney). If you were meaning the Avengers, then we’re getting somewhere.
Yeah, although I've seen some analysis that the problem is that the original Star Wars movies never really got a big distribution in China, so they're not familiar with the lore. That means that when there's the big reveal of Luke Skywalker at the end of Force Awakens, the general reaction in China was "So who is that guy?"
As for the MCU being the only thing keeping Disney afloat, that's absurd. Between the TV networks, the parks, animation, and consumer products, they're doing fine, as their stock price and the recent acquisition of Fox shows. People have been predicting the demise of Disney for decades, and yet here they are, the only independent studio left in Hollywood, and consistently #1.