> Cementing the use of phone numbers instead of email addresses as the primary identifiers in people's digital lives
From my experience RCS is just a backup/temporary holdover system to keep SMS usable as is, since people are increasingly using regular chat apps like WhatsApp. Plus as long as spam/identity is a major issue then phone numbers will be a part of verification systems. They will use anything they can get to make it harder to abuse. Whether the root ID is phones or not doesn't really make a difference if a phone number is required at some point to use a service.
There's a large split here between the US (where people largely use SMS and now RCS) and the rest of the world, which largely uses WhatsApp, WeChat, or very few others.
I'm of course also just as critical of having Meta run the world's communication industry instead of Google, but that's the duopoly (or rather two monopolies split geographically) we're headed towards. Cheering on RCS as a way out of it, instead of directly towards it, is deeply misguided.
That said, at least WhatsApp provides some basic features that XMPP has supported more than 20 years ago (multiple devices being logged in simultaneously, synced message archives etc.) – I'm not holding my breath ever seeing these on RCS. As a pseudo-federated standard, protocol and client development will always be much more complex, and looking at the baseline complexity of the RCS specification powering the few existing features, I'm just not seeing it happen.
Needing my phone to be powered up and connected to the Internet to message people from my computer in 2025 is absurd.
From my experience RCS is just a backup/temporary holdover system to keep SMS usable as is, since people are increasingly using regular chat apps like WhatsApp. Plus as long as spam/identity is a major issue then phone numbers will be a part of verification systems. They will use anything they can get to make it harder to abuse. Whether the root ID is phones or not doesn't really make a difference if a phone number is required at some point to use a service.