Stores like FYE and Suncoast shut down possibly in part to the internet, but I think an even bigger reason was because their prices were easily squashed by places like Best Buy, Walmart, and Target. I think blaming the internet for everything a lot of those things is pushing it. A lot of smaller stores closed up shop not because of the internet, but because bigger stores (with better prices) expanded and stole their business.
Other places shut down because of business practices that were no longer working (or were bad from the beginning.)
Sure, you don't get to find a lot of the more "niche" titles in the stores anymore, and yeah, 10 years ago you likely *could* but 10 years ago you had companies like Anchor Bay, MGM, Image, and Blue Underground putting out tons of product. Now things are a lot different, most of those companies have changed drastically, because of the climate and the fact that people seem apprehensive to plop down money like they used to they no longer take chances. That, or they're just no longer interested in the genre.
I for one love amazon, I use websites like amazon, facebook, diabolik, and ebay just as much as I frequent Hastings, Best Buy, or random video/second hand stores.