Catman - I realize your question on monopolies was probably rhetorical, but here's an answer anyway:

It isn't illegal per se to be the only company doing something - but it may become illegal if you try to use market position to force out other businesses that want to do the same thing. If Dining a la Card is doing a bad job (I would tend to agree), sounds like an opportunity for a competitor. (Of course, there are those nasty start-up costs. )

A company that does something so well that it has no effective competition is often called a "niche" company instead of a monopoly.