I think they mostly died when GChat turned off XMPP support and became a walled garden.
Most of the protocols supported by Trillian were walled gardens too - AIM, ICQ, MSN Messenger, Yahoo Messenger, etc were all proprietary.
I think they mostly died when GChat turned off XMPP support and became a walled garden.
Trillian had paid full-time developers too. I'm not sure what'd they'd be doing differently to what Trillian did.