I think RCS is being framed incorrectly. It isn't a competitor to WhatsApp/telegram/iMessage it's an update to SMS

If they bought out another competitor all that would happen would be one more chat client that 20% of your contacts use if that.

With RCS, in order to supplant SMS it requires co-operations with telco. It's there to see increase base line support.

Maybe telco would have been okay with e2e encryption although I highly doubt it. Once the baseline RCS standard is put in place. It maybe possible to implement e2e with an OTR client side extension.

RCS is the successor to or replacement of SMS/MMS. I for one will be happy when I no longer have to ask: "how do you want me to send that to you? Email WhatsApp or telegram?"