Publishers should be able to price their product at whatever levels they want. They got into trouble when they got together to agree on set prices.
Ebooks are an interesting thing. The Apple and Kindle Ebooks seem to be licenses to view the content, unless you illegally break the DRM of the content and load it into callibre or a similar software. You can't buy an ebook and then sell it when you are done. You can't buy a used ebook :)
Physical textbooks are getting that way too, coming with 1 time licenses to study problems that your teacher may require, which eliminates the used text book market. Ultimately, they are adapting their profit model to extract the most they can out of the existing market, similar to how Dice hosts advertisements on slashdot and calls them news articles.
I would hope that these trends push people to abandon these platforms, but history tells me that most people will stick with it because its good enough (some people gradually edging out of the market, but they don't matter). Will the people sick of these moves make their own platform? Hopefully.