There is room for 3rd party app stores. Epic will argue that Apple does an absolutely ghastly terrible job of curating the Apple app store, as Apple really has little incentive not to suck completely. The EU court will agree. Apple will spend a year or two saying “it can’t be done”, then issue a signing certificate to Epic.
Without the requirement that all apps able to be purchased on all stores at similar prices and still under Apple's review process then apps will flock to the store that makes them the most money and fewest rules and users will have no choice but to acquire that app via that store. If I have to go to X store for an app I need I don't really have my choice of store.
Do gamers like the current culture of having to have Origin, Steam, UPlay, Epic, GOGs, Blizzard Store, for no other reason than large middlemen playing Civ with marketshare and exclusives?
I think if this issue was solved we would see less people desiring Apple to have such tight control over their ecosystem because it would mean that for users that like Apple's store opening up isn't a strict downgrade for them.