Signal seems to be going in the opposite direction and announced the end of SMS support because of the lack of SMS security https://signal.org/blog/sms-removal-android/
Meanwhile Google is pushing RCS hard https://www.androidcentral.com/google-evolve-android-messages-chat-using-rcs-shelve-allo
Looks like everyone wants SMS to die but there isn't a consensus on a replacement. So I can see the use for an unified chat app. Not sure about SMS support however.