RCS can be encrypted. Whether Apple chooses to do so is yet to be seen of course, but I'm guessing they will reserve encryption for "blue bubbles."

Yes, as a non-standard google extension that is not guaranteed to be present.

To illustrate the issue, imagine apple added support for "encrypted RCS" that was just iMessage's message blob stuck in an RCS blob (this is essentially how google's encrypted messaging solution works). Would you be ok with that being presented as "encrypted RCS"?

If only there was an encrypted chat service, that works on multiple devices, has a single identity across all of them, etc. Oh well, guess we'll all have to buy iPhones to use iMessage.

There is matrix.

Correct! There are numerous options available across a wide variety of platforms, and yet people obsess specifically over iMessage because of perceived (and seemingly US only?) obsession with blue bubbles.