With the current pricing model, I'm undercutting the possibility of any competitors to arise, plus I'm not sure how ethical it is to charge so much for a service that's basically a monopoly (i.e. price-gouging) when I doubt font designers even have very high margins as it is.

I've considered doing this though, and the fact that you're validating it now makes me think it may be worth testing it out for a little while just to see what happens.