I don't think the brick and mortar stores are going away any time soon. There are just too many people out in the "sticks" that don't have access to high-speed internet, whether through cable, DSL, wi-fi, or FOIP.
DSL has a limit to range, but the biggest limit is the old copper wire that is still heavily saturated in many areas. Cable is if you are lucky out in the sticks to be on a road where the trunk flows. Wi-Fi you have to be in range of it, and that is about 3-4 miles currently (little high). And FOIP is barely hitting major cities now. Satellite I don't really cover because of the high cost and only one of 2 providers offering it.
Why do I start with high-speed internet, well it does connect slightly to Blu-ray (go with me here). These same people out in the sticks are happy with what they got, and for the most part not everyone can go out and get the latest and greatest. They just don't have the money right now to do so. Not to mention the prospect of replacing your movie library with Blu-Ray, like video to DVD (yes, blu-ray players will play dvd's).
As it is most people are still confused about the change over to digital tv. Around me there are only 3 stations that have switched. NBC and CBS still haven't started broadcasting in Digital.
While yea, I don't really discount the odds of Blu-Ray being replaced in x years, something is going to have to become as easy as DVD in order to replace it for the masses, not something that looks exactly the same but just sounds different.