On the front page, we actually have a kind of live box, called status updates. That hasn't been used much, either. While I realize it isn't exactly the same as a *realtime* chatbox, it allows users to post something that is visible on the main page, and allows others to respond to it in the same location of the main page.
I don't mind the work of maintaining something that is used, but, like Chris says, if it is only the three or four of us that uses it, IRC is a completely free, no-risk alternative. No signup is required on 'another' service, just the download of a client.
As an attempt to solve this in a congenial way, maybe we could prove its usefulness by employing the status updates first, and seeing if they make a small attempt to fill the void before committing to a purchase?
Incidentally, the IRC channel at OFTC - #gamersonlinux remains open for anyone interested. I wonder if there are any plugins that put an IRC window on the front page.