How is this a Google problem? Ask your bank.
> FWIW you don't really need an app store, you could download APKs off vendors/publishers.
Very evidently I do.
It seems to me there is very little stopping there being a whole pile of competing Android app stores out there. Technically there's nothing stopping it in fact, as the existence of FDroid illustrates. It's purely a matter of convenience - which is the same thing that drives Chrome's dominance on Android despite there being better browsers available for free. The play store app is pre-installed and is almost a one stop stop for all the apps you could possibly want, so who is going to bother loading another app store?
Turns out that edge in convenience is enough to create an effective monopoly in app stores, for most people anyway.
Even if there was a popular alternative, there will simply be apps only on one store out of convenience. Just look at the PC market.
And most of the time PC leads to multiple releases as platforms tend to make it as easy as possible to release across multiple.
Sure the majority of games are on one but a significant fraction of the popular ones are on multiple.