XMPP was actually fairly successful. It was just embraced, extended, and extinguished by the major companies that provided services using it. Google, Facebook, and Atlassian all used XMPP for their chat clients. You could freely interact with all of their chat solutions using XMPP clients. XMPP support for each one of them went away one by one.
The environment outside of major providers was (it definitely is) kind of janky. If you can set up a server application it's not hard but it's not exactly easy to get started, or get people on it without handholding (from my own experience).
The environment outside of major providers was (it definitely is) kind of janky. If you can set up a server application it's not hard but it's not exactly easy to get started, or get people on it without handholding (from my own experience).