Xmpp didn’t fail - the major companies who all built their messaging platforms on it just turned off federation. RCS is still focussed on phones only, so it’s

Xmpp didn’t fail - the major companies who all built their messaging platforms on it just turned off federation. RCS is still focussed on phones only, so it’s a non starter IMO. But it’s driven by the same companies that charge the equivalent of $1000+/mb for sms delivery, so it’s unsurprising that customer needs are not really their first priority.