Also, in Google’s attempt to push RCS, they’re narrowing what application are allowed to use the SMS lib. They already partnered with Samsung so Samsung would removed RCS support and ostensibly deprecated their own Messages app for Google’s.

Google’s long-game is to only have one SMS app on Android, their own, much like the way they’re closing off the rest of the Android ecosystem slowly from every other vector.

Trying to support SMS on Signal long-term would just be an exercise in futility.