I understand and you are of course right. Here's the question, though: what if everyone does what I do, i.e. look at the store and then buy from Amazon, etc? Isn't this the tragedy of the commons? Then BB will close (like Borders) or would have to radically adapt (like B&N, who currently carry half books half toys in most stores).
Luckily for all of us who enjoy perusing BB, they are (currently at least) avoiding both fates since (i) they are pretty much the monopoly in electronics stores and (ii) there are a lot of customers lazy or clueless enough to just buy their stuff there rather than online.
Then either BB will start charging an entrance fee, or they will start charging the manufacturers display fees. At that point they can reduce their prices to about that of online shopping (since you have the value added of being able to purchase the product immediately, but your time spent driving plus gas plus maintenance costs more than shipping).
Luckily for all of us who enjoy perusing BB, they are (currently at least) avoiding both fates since (i) they are pretty much the monopoly in electronics stores and (ii) there are a lot of customers lazy or clueless enough to just buy their stuff there rather than online.