Apple has a "monopoly" over the app store as much as Disney has a monopoly on Disney movies.
I explicitly cannot do this for iOS apps. There is just no way for me to get my app in front of people's eyes without paying the Apple tax.
If I was prevented from distributing my movie somehow by Disney, you might have a point.
Disney's not going to put it in their online store, though.
In the case of an iOS app, you can sell the source and let people build it on their own Xcode installs, if you like.
Then we'd all have a half dozen completely incompatible physical media players and so on.