There are at least two big differences between the hardcover/softcover debate and ebooks. One is that the consumer has the choice between an expensive hardcover and cheaper softcover, while obtaining what is usually the same produce (just different quality paper and binding). People who envision a world in which we only have ebooks without having pbooks also envision a world in which that choice is non-existent. So publishers are forcing everyone into a higher price bracket.

The second big difference is discounting. When there is a surplus of pbooks in the market, publishers feel compelled to discount (often deeply) the price of books so that they are not using up valuable retail space or less valuable warehouse space. That motivation doesn't exist in the pbook market, so publishers can keep the price of ebooks artificially inflated for years or decades. Will it stay that way in the long run? I doubt it will if consumers are willing to push back.

Of course there are other issues too. Many people see ebooks as value diminished products because they are losing a lot of their rights. Simply put, DRM ensure that consumers will not be able to maintain their purchases in perpetuity. At a minimum, they are at the publisher's whim when they need to replace their ereader. My experience with electronic devices suggests that batteries are rarely usable beyond 3 years. Paying $20 for a book that will die with your ereader is pure nonsense. Another issue is resale, which, of course, you don't have the right to. So if you view ebooks as throwaway items and pbooks as something that can be kept or resold, is it any wonder why people are only willing to pay a tiny fraction of the price for ebooks?