Buying an Android phone is no longer enough — Google wants you to subscribe too
(www.androidauthority.com)
Personally I don't think the side loading will kill them. It'll happen and nothing will change.
Perhaps the ai bubble burst could damage them enough, but they are way to big of a monopoly to fall. And android alternatives still scare people as unlike PC, you may brick your phone, or be locked out of apps due to play services