I think the RCS users are quite happy that iOS has RCS now. Though, they may be disappointed that Apple didn't set up an RCS server like Google did, because now

I think the RCS users are quite happy that iOS has RCS now. Though, they may be disappointed that Apple didn't set up an RCS server like Google did, because now people find out that their carrier doesn't do RCS so they're still missing out in the advantages. But, when RCS works, it works well. The stupid compatibility hacks Google and Samsung and everyone else implemented to make SMS/MMS pretend to be good at group messaging (like the ways they indicate emoji reactions) no longer need to be encoded in human-readable form. The encrypted component of RCS was a Google special and I think everyone knew that. People wanted Apple to immediately take up Google's encryption spec, but Apple waited for the GSMA spec to be updated with E2EE which is a much cleaner solution. The opponents of RCS have a point; using RCS is a bit like using your ISP's email servers in that the quality of your ISP determines how good of a time you'll behaving with it. There are also many advantages to full RCS support that nobody seems to have implemented yet. Things like video calls, or sending money over text. No longer needing third party services like FaceTime or WhatsApp to do video calls is a step in the right direction in my book.