Android has had alternate app stores for years. I don't recall any of them being a panacea for poor struggling devs held captive by Google Play. I stopped offering my apps on any of them as it was never worth the bother.
What problem is this trying to solve for who exactly? I don't see any way this ends up as a win for small devs.
And let’s not pretend that Apple is making a lot of money off of Indy developers. Most of the App Store revenue is coming from pay to win games and loot boxes.
Where do I sign up?
This is the free market competition that tech is supposedly in favor of.
People are already upset that their digital purchases are controlled by Apple. Wait until the startup that they bought stacks of software from goes bust and all of their app purchases are gone.
And the point of this monopoly busting legislation was to create a bigger monopoly?
Google and Apple would still be welcome to operate their own stores. A 3rd-party cross-platform store would compete with them, hence no monopoly.
Edit: I guess you read my comment to mean "Apple's app store would come to Android" or vice versa? That's a possibility. I'd prefer that to the current state of affairs where no direct competition is possible