If people wanted to do this theyd be self hosting xmpp servers already. No one wants to write and maintain the code and infra for things like this, you are grossly underestimating the effort involved here.
Now some IC somewhere in the company who is at the end of his rope and sees the company as a dead end, sees an opportunity. Why not advocate for this project, get real experience building something greenfield in a brand new domain, strengthen their own resume, and finally have a way out of their strut? It's not like they're gonna stick around maintaining what they built.