It’s not the reason, but it certainly is a reason.

Another reason is. That it is an old protocol from the late 90s. And there isn’t a lot of Buzz about it these days. A lot of the problematic centralization we all now recognize was just becoming the norm.

Feature parity at the time is also another big hurdle. Things we all take for granted especially in this day and age Avatar profile pictures etc. Jabber/xmpp did not have that for years. It may be a useless feature in terms of sending messages. people still like personalization etc. And it’s hard to convince people to switch if they have to give it up.

Jump to today. And arguably services like Twitter Mastodon Facebook Etc all sort of fill that Niche to an extent. Maybe not as well. But enough again that it’s going to be hard to get people to switch to yet another system