I think there's a useful analogy between these publishers and those companies that buy the rights to medicines developed by small research labs, and then raise the prices several fold. The question is not "why do they charge so much?", but rather "what was it you thought would stop them?" If there is no market-based restriction on their ability to raise prices, and there is also no government-based restriction on their ability to raise prices, then it is not too surprising if they raise prices. Not that this makes it right, of course.
