I suspect you're right. This line of questioning is to get at whatever perceived injustice Den is bitching about with these posts.

If they're mostly just recouping costs inherent to the technology, then having the government step in to prohibit these fees isn't going to help anyone (shocker!).

I'm not sure what their marginal costs are, but my guess is that credit card issuers aren't making runaway ROIs way above their opportunity costs, so competition is probably working.  I mentioned below that I think there's a real demand for the convenience of credit cards over cash & checks, and that many customers/merchants are willing to pay higher prices in order to use digital payments.

SimpleStacker

I guess the question is what the friction is in the system that prevents competition from driving those fees down.