I was using the Internet before the WWW, and there was already a pretty good ecosystem from nerdy stuff to consumer-usable. Email, Usenet, Gopher, FTP, IRC, were all widely usable.
Gopher especially made a great way to index and search (with WAIS) things on multiple different services, without being a mess of text/hyperlinks/images/sound/video in a hairy ball like the WWW.
RCS is not end-to-end encrypted, so their bubbles will remain green.
Google's proprietary extensions add E2EE, and Apple's not going to pull a Beeper on Google.