Let's look at something closer to this situation rather than general purpose computers. Mobiles work with different paradigms all around, especially when compared to Windows (or Linux).
There are free alternatives to Google's Play Store and yet developers still choose to pay Google's cut to have access to it. This tells me whatever benefits the "official" app store provides on each platform outweigh the disadvantages (costs) even when free alternatives are available.
> The AppStore still works on mobile because they force it.
Is there any solid reason to believe the AppStore only works because they force it, while seeing the Play Store work just fine even with free alternatives around? And users even go out of their way to get access to it.