Don't choose iOS if you don't want only one place or iOS Apps.
You're right, you can buy PlayStation games from many places, but Sony will still get their 30% cut, they still have to be approved and tested by Sony. No one can just make a game and stick it on a Walmart shelf, it has to be licensed by Sony for it to even load on a PlayStation. So if the argument is that there should be side loading, but Apple Still has to test, approve, and make sure the Apps follow their guidelines, and Apple Still gets its full cut, then I would be ok with that. But I don't see any benefit to that.