Earlier quoted context omitted.
You haven't looked that much into it then; RCS has encryption[0], and works great for me. (I have an iPhone 13 Pro & a Pixel 6 Pro. RCS works as well as iMessage for Android-to-Android devices, for me.) [0]: https://www.gstatic.com/messages/papers/messages_e2ee.pdf
Is that RCS having encryption or is that Google providing an extension to RCS only with their Messages app? And to what degree does RCS with encryption have buy-in from American carriers?
[0]: https://en.wikipedia.org/wiki/Rich_Communication_Services