The misery of RCS ultimately was rooted in money, not technology. Carriers wanted a way to monetize messaging services on LTE like they did in the 1990s with SM

The misery of RCS ultimately was rooted in money, not technology. Carriers wanted a way to monetize messaging services on LTE like they did in the 1990s with SMS. They thought that inventing a new standard, ostensibly built around SIP (ie more integrated into the telco session layer than SMS, which was a bit kludgier), would be the path. What they failed to realize what that LTE brought easy access to data, and in particular OTT messaging like WhatsApp. Consumers, remembering only too well the horror stories of being gouged by telcos for heavy SMS messaging, were not inclined to trust the carriers. So WhatsApp etc. took off while RCS stagnated. On the technical side, vendors soon discovered that every telco wanted to do RCS slightly differently, and that implementing RCS in an IMS network was not as easy as slapping in an app server. So when Jibe showed up, a lot of the air left the room. Problem was, the telco people saw precisely what Google were doing: taking away a potential revenue stream from their control and monetization. So again, things languished. The technical people I worked with at mobile operators across this time were very sharp people who could make most anything work. But the leadership was so terrified of losing money, and so bad at making money, that many good plans never saw the light of day.