Gramsci ugh, I have been wondering about this for a few weeks now. It does seem like Google is trying to tie RCS to hardware in a way that graphene prevents. Well I don't understand all of the technical details, it is a little understandable from the point of view of wanting to have absolute control over a device/person and wanting to prevent spoofing.
It's an uphill battle, but it's going to push me further towards third party E2EE options, and I'll just have to deal with getting my friends onto those platforms.
I suppose the other approach is that somebody could come up with a way to implement RCS outside of Google messages. I know that's been a very rocky situation.