I think that's a shame. Some of my contacts only have WhatsApp, and I am definitely not gonna install that Spyware. So to those, I am still sending pictures by MMS.
I was a MMSC developer over a decade ago, don't ask what most of the MMS traffic was.
Thankfully, it's not driven by Google, just "approved" by them. You don't want to use a Google technology for thinga you want to continue to exist 4 years from now.
The current situation means that people who are directly connected to Google's own Jibe infrastructure can message carrier-operated Jibe deployments. But they can't message third party RCS networks or vice-versa.
Pure speculation: Google got frustrated with carriers moving too slowly even after acquiring Jibe. I understand carriers not being compelled by Google's lack of vision for mobile messaging then. Especially given that Apple won't give a damn.
A few years pass and Google decides to pivot their messaging services once again, and that now is the time to push RCS for real. Google managed to convince big carriers on several continents that Jibe is the solution. And they probably think the small ones will eventually cave in.
This is only speculation, but it's Google. You don't get promoted for making an existing messenger work, or work better. Better to abandon it and join a team making a new messenger.
And even if there was: I really don't like the idea of an (at least somewhat) carrier-controlled messaging service. Especially the lack of multi-device messaging/not being able to access my account without my phone is really frustrating.
We had all of that with instant messengers in the early 2000s (proprietary or open/federated) – RCS seems like a big step back in that regard.