How will it be a good thing for all Apple users since Apple users use iMessage and don’t give a crap about SMS or RCS?
Maybe it it was someone else besides google pushing RCS it might have a better adoption rate. But by this time next year google will have moved to another message app.
You seemed to have left out when Fortnite was removed from the play Store and lots of fake scam apps popped up in their place. So yes things would most likely change.
Plus there are a handful of app developers would would love to leave the App Store. Basecamp and proton come to mind. So now you have at least 3 app stores to add.