Google Play Store won out on Android simply because the multitude of stores was a nightmare for customers. They don’t want multiple stores, they want one store on this phone, that will also be on their next phone. Any ‘monopoly’ wasn’t seized by Google, it was pushed eagerly on them by customers craving consolidation and simplicity.
Same for me, I don’t want 5 blasted stores on my iPhone. I want one store and run by someone I trust. The same goes for my Switch too, I’m quite happy for Nintendo to run the store for it. If I don’t like how they run it, I’ll get a PS 5 or XBOX. That’s where the competition is. I have plenty of choices thanks.