@karatekid@mastodon.social I think it's still possible but it may be getting more difficult. I suspect that Google may continue to lock it down as much as they need to, the point for them is to stay in power and keep making money.
If Google sees a threat from some popular free alternative based on Android then they can lock down Android more to hinder that alternative. So, if you want to build something free and sustainable it's better to not base it on Android, go with GNU-like #MobileLinux instead.