Although what you refer to certainly does occur, I believe that the converse occurs far more frequently. That is, a prospective buyer goes into a brick and mortar store, picks the brains of the salespeople, and then goes online and looks for a better price for the desired item. Amazon has cleverly handled the shipping cost issue by offering its Prime membership. It had been about 79 bucks a year, and was recently raised to $99, but it offers free 2-day shipping on anything Amazon sells directly. There are also some other benefits like their Netflix-like movie/tv site, free music, etc. The clever part is the brand loyalty. Once you've absorbed the sunken cost of the annual membership, the "free" (from further charge) shipping usually makes the total package cheaper from Amazon.
#14 I have Amazon prime and I buy way too much there....
I went to my account and saved the list of past orders for the past 2 years. Now I know why my credit card bill is so much. I order stuff and it arrives in 2 days or sometimes maybe a few days longer. I would never be able to find what I buy as quick and easy if I had to drive to multiple places.