Weirdly enough, messages seem to be the only thing I see the general public being ok with diversifying.
Everyone I know uses different messaging apps, I have active conversations in signal, telegram, Whatsapp, messages(SMS), messages(RCS), discord, and matrix.
sms is essentialy just a confirmation code delivery protocol tho? (like i have around 100 "chats" with just confirmation codes in them and ZERO conversations...) and i don't see anyone using rcs mostly because of EXTREMELY poor reputation of sms messaging...