HipChat Alternatives
github.com
github.com
Is there a technical reason for it? Is XMPP broken in some way? Or is the chat space simply full of pathological cases of Not-Built-Here Syndrome?
XMPP's based on XML anyway, so implementing inline media and extra features sounds easier than rolling an entirely new protocol.
But perhaps some of the proprietary systems use XMPP internally anyway? After all, it's used for more than just chat clients nowadays.