E-books are destroying the second-hand book industry in the most part, although not in some areas (notably libraries, of course, but also many textbooks which are so expensive and complicated to buy). E-books are far more efficient, resource saving, and convenient in every way, and they will likely soon kill the industry.
I think ebooks are definitely killing small bookstores in general. There will be a secondary market online to sell used books. Eventually, some time in the next century or so, we may discard printed material all together. It does seem to be the natural progression of things. The only problem is what happens after some massive electronic disaster.
Publishing of books is a whole different world than it used to be for sure. Those of us who love to browse in book stores, particularly second hand book stores, are going to be at a loss in a few years. Of course, there's still a backlog, but fewer actual books will now be passed on.
E books are usually cheaper and easier to get access of so if they are not destroying second hand books now they will be doing so later on. The cheap makes people interested and than not having to carry a large book around is another upside. People want to have it light and easy.
Having seen some very predominant and thriving second-hand book stores, I do not believe the that e-books are destroying the industry yet. I believe it will continue to degrade, but there will also be people who like paper books. That is until we die off, those of us that grew up with them, then it will die.