We pay a similar amount for HipChat, which is basically the same thing as Grove. Most of our users would eat up far more of the costs of just using a service like this dealing with setting up IRC clients, explaining IRC to them, etc. rather than just pointing them to a web app, which is far more familiar.

The problem is, "hosted IRC" is a ridiculously bad marketing strategy. IMO, Grove should view IRC as a backend implementation detail, and not any part of their public offering. The only people who are going to care that Grove is backed by IRC are exactly the people for who hosting an IRC server isn't a big deal for.