Re: Enterprise apps? We've heard of them.
"I guess you can still install apps from outside the playstore which can access these features"
Yes, and in some ways the 'new method' (individual approval of each application NOT certified by 'Google Play') is better than the old one (wildcard enabling of any application install from outside of 'Google Play') though I have had to jump through hoops a bit to get it to work so far.
But this might not be possible if the Android OS is updated to simply exclude ANYTHING that wants access to 'certain features' (from permission flags in the 'manifesto' let's say, similar to now) when those feature requests are on 'a list' and there's no cert or other 'permission mark' from the Play store's signage info to allow it....
I also don't know what affect this will have on any legacy home-brewed and locally signed APKs, which [for now] can be made available via a web page or be directly copied into the Android's file system via USB. Enterprise applications needing access "to everything" might STILL be possible, doing it this way. (edit: someone else calls this 'side loading' I guess; not a term I'd used before, might have seen it, didn't stick)
Google is (wishful thinking?) *trying* to protect end-users from themselves, without becoming TOO much like Apple with _THEIR_ store (bans because "Apple just don't like it"). Well, I hope so. And apparently it's a reaction to rogue applications. No surprise, but little excuse for THIS kind of "solution".
Google could offer a better method, using something similar to 'Firebase' for authorization keys (let's say) that are verified at install time from the Google Play store. That's not ideal, but at least it would help to control the "rogue" behavior by adding some extra 'permission steps' and not outright BANNING functionality.
And, it COULD get worse... they could become 'Apple'. Or even MORE like them.
For some reason it reminds me of Firefox making changes from 56 to 57...