I think the issue here is we need to separate the quality of the films, which is an artistic matter, and their business practices as a company. I am in full support of gutting monopolies (or if you prefer, in this case, quasi-monopoly), and if we did that with Disney, the company, we'd have much more diversity of films (It used to be the Big 7, then the Big 6, and now with Disney-Fox merger, it's the Big 5). As for the quality of the current films, film is subjective, just because a lot of people think they're quality, doesn't mean everyone does. But when a lot of the top grossing films are owned by the same company (In 2018, Disney had 4/10 of the top movies, one of the others, Deadpool, now owned by Disney), that signals there's a large market that is
not being catered to.
As for me, Disney films have not been quality for me, personally--they're overly formulaic, and an over-reliance on bathos, subverting emotional moments with anti-climactic comedy, and they have a family-friendly philosophy that works fine with their animated films, but they carry over to everything (RIP Deadpool). And in the case of their action films, an over reliance of CGI action sequences, particularly at the climaxes, makes it look like toys flinging at the screen, rather than anything with emotional catharsis. It's what turned me off with Marvel movies, what turned me off with Star Wars. And I have little to no faith Disney will do X-Men and Deadpool justice. I joke about it, but I do seriously believe Disney should not be owning this many major properties.
And it would take a lot to dethrone Disney, though to explain what we should do, would be a political matter, and I'll leave that part out of the forums.