The book stores are going the way of the media stores like HMV and Virgin. Rental stores relying on physical media like DVD's and BD's are next. It is just too expensive and cumbersome to do business like that and new technologies are available.
Given this site, I can't believe that no one has mentioned the impossibility of finding a hobby or toy stores anymore. Growing up it seems you couldn't throw a rock without hitting one.
Funny, I had been trying for years to visit the small toy soldier store just off Oxford street, I think it was called Under Two Flags, but I'm not sure. It was on little St. Christopher street which is one of the wonderful finds in London. Any time I was in the area, and this is for something like 30 years, was always on a day that they were closed. Finally, a few years ago I was in the area on a Saturday and knew that finally I would have a chance. So,I walk down there and couldn't find it. I finally stopped in a store across from where I thought it was and was told that it had closed up about a month before. Well, I did try.