> They can make a "standards compliant" RCS which will be able to connect to literally zero carriers or servers on the planet.

I call bullshit. If iPhones can connect to RCS, so can other phones.

Their app does use a weird protobuf spec of their own design, but that's for synchronising messages across devices/their web UI. RCS doesn't really do multi-device the same way iMessage does so they had to add another layer. That's not part of RCS.