AnotherBloke

Yes RCS is not that new, but the article it right that it is still not ready for any and all platforms, since in practice it lacks the universal interoperability of SMS, i.e., whatever phone and carrier you use, you can send and receive SMSs without installing any additional application and without registering to any additional service (no Apple/Google/Samsung/Meta/etc. account necessary). Therefore I also agree that only a solution "backed by carriers, governments, and tech platforms alike" could replace SMS, and RCS is (still?) not such a solution.

Outside of the US of A, people do not use iOS solely for iMessage, since there are often many more Android users than iOS users. For example, in my family/friends groups (in France) we use Whatsapp, Signal, Discord much more than iMessage (incidentally, for group calls we use the same, or even Skype, but literally never Facetime).