It's not ideal and pisses me off it took this long, but the technical implementation and UX is not at all bad now that we're here. The big 3 American carriers are in on this standard now, and Ma Bell's RCS-capable messaging app that is preinstalled on Android phones is basically indistinguishable from Google Messages even down to the logo. What I mean is that the UX isn't that "carrier-y" and more dumb-utility esque. Lastly, Google may not install their APK version as default on OEM phones- but the binary is readily available on the Play Store and Android has a myriad default app settings, including for messaging.
Look, Google fucked up for years and it's actually my biggest gripe with them (ceding messaging to the loonies in Cupertino in the US) but at least we're now at the point where all American Android users will have an interoperable standard, and since iMessage is a cancer in America particularly, well, it's okay if RCS takes longer to reach critical mass elsewhere.
There are parts of making a chat platform that are hard. Want to support end to end encryption? Very hard. But google doesn't give a shit. They're going to warehouse all messages in plaintext in a forever database that they'll use to train NLP models anyway.
Interop between a dozen different providers is hard. But google isn't doing interop with a dozen different providers. They're doing interop with themselves. They can say "oops this API sucks" every four months and that's fine.
How Google can make Docs a thing and make it work well but can't figure out chat is bananas. Or gmail. What is chat but email with message size limits and the explicit removal of interop as a feature?
Look, Google fucked up for years and it's actually my biggest gripe with them (ceding messaging to the loonies in Cupertino in the US) but at least we're now at the point where all American Android users will have an interoperable standard, and since iMessage is a cancer in America particularly, well, it's okay if RCS takes longer to reach critical mass elsewhere.