Android is open source. There's nothing saying that we, as the community, couldn't fork it away and use it as our own base, at least in the meantime.
That's why Lineage is called Lineage, and Graphene is called Graphene, because Android is a trademark, but nothing stops you from just forking off, say Android 16, and not relying on Google at all anymore. Make your own security patches and everything else.
Instead of Android apps, we'd have lineage apps. And lineage apps would work on lineage devices and graphene devices only.
Instead of .apk it would be say .lpk and the conversion between the two would be seamless.
so that anybody who built an Android app could with just one single command also build the app for lineage or something like that.