Any app can prompt you to install another app without root on Android (since Android supports installing app packages outside of the Play Store). So if somebody wants to make an app store, they just need to publish an app that provides downloads to other apps and that's it. New app store. It doesn't affect how individual apps are sandboxed either. How apps are installed doesn't change the security model of the OS. Now, Google's position is still problematic because they clearly use their position to push the Play Store on everybody, but it shows that separating the store from the OS actually is quite possible.
And seriously, Apple is a hundred billion dollar company. I'm sure they can handle this if push comes to shove. People need to stop defending these companies as if they need the protection.
And seriously, Apple is a hundred billion dollar company. I'm sure they can handle this if push comes to shove. People need to stop defending these companies as if they need the protection.