The one thing that feels off to me about Google’s implementation is that it’s not vendor agnostic and all comms would need to go through Google’s servers to work. The E2EE bit is an entirely Google specific extension to RCS, for example. The last thing we need is another chromium situation in a different area.
If it wasn’t a Google specific extension, phone networks around the world would need to pick up the pace and adopt RCS, but also they’d need to keep up to date with the latest version of the standard to ensure the functionality is supported. Now, looking at phone networks’ previous track record, they’re really not going to implement it unless they’re forced to and they’ll do so at a real snails pace.
At this point I’d agree that Apple not adopting RCS is really not helpful here.
I feel the EU’s Digital Market Act that’s forcing messenger applications to be interoperable with each other is going to be a much more viable option towards that perfect world scenario. The IETF is even fleshing out a common protocol for it, MIMI with MLS.