Is it really ethical to try to get as much money out of your customers? If you are making a profit after all costs are considered, how much profit is too much?
The question is maybe not too important when applied to something like an e-book, but it becomes different when applied to something people think they cannot do without, like a college education or healthcare. In those situations we have seen vendors will gouge you for as much as they can get, which ends up being as much as you have.
We as a society need to rethink whether that should be considered acceptable behavior. I don't know if legislation is necessarily the right solution (I am inclined to think it is not) but at the very least people should feel shameful for being so greedy.