I agree with all of this except for the claim that "Google wanted this". I think Google is as annoyed with this situation as everyone else. They would've preferred to have their own iMessage alternative, but they launched a dozen which all failed, so they went "Well, we can't make our own that people want to use, so let's get the carriers to make an upgraded version of SMS". And then the carriers didn't want to do that but the "it's decentralized!" message stuck with users and even a few governments, so now RCS is the worst of all worlds: it's a de facto Google service, but with a janky, half-baked decentralized protocol, where Google has limited capability to improve it compared to a native Google chat app.

It's a complete shitshow.