Re: lawful interception, when carriers switch to IMS registration (as required by Apple) they should also get access to Jibe's standardized API for law enforcement tools (there's a spec for that, I forgot its name). However, just the fact RCS payloads are E2EE in Android-to-Android communications (and soon Android-to-iOS too, hopefully) might already be illegal in some places.
Google flip-flopping around its mobile IM strategy for a decade and then around carriers with RCS is getting harder and harder to understand. Pulling the rug under carriers in developing countries, who weren't interested in the drug dealer marketing tactics, is only going to solidify Meta's dominance, as doing business with WhatsApp has proven to be a much safer and saner bet all along.
Hate to agree, but with the underhanded tactics that Google is pulling with RCS, Meta is actually the sane and ethical company in the room.