Like imagine if instead of investing in RCS, Google instead created a web-based "Advanced Messaging Protocol" or something to that effect, which specifies capabilities roughly in line with those of RCS. The big guys like Google, Apple, Meta, and MS would run their own servers, but there'd be no reason why smaller players like FastMail and Proton couldn't also run them. Most users would just roll with the major providers pre-configured on their platform of choice but more savvy users could choose their own.

That could've rolled out and been adopted and iterated upon far more quickly than RCS has.