You're going to see more of that going on in the future. Some of my clients go to upper end plumbing and electrical shops, spend several hours with the sales person developing a list of what they want and what will work, then going home and buy it online.
The customers in question aren't very nice people.
I think that if I ran a shop for my business and kept having the above problem, I would have a politely-worded sign in the window saying something along the lines of "We aim to provide the best advice and general customer service. If you are only coming here for advice, please at least provide a donation to ensure that we can still run a business and you can continue to get advice you can trust when you need it".
Many of those places won't help you anymore without a nonrefundable deposit.
These businesses aren't run by very nice people.
In recent years, I personally have only encountered one shop selling technology with customer advice that I would recommend without hesitation. Most big-name shops in my experience employ people who are capable of reading the information which is also written next to the product's price tag. I certainly would not pay if I thought there was a possibility that I would receive the latter type of service.
I think certainly one big reason for the decline in popularity of shops is poor customer service. In the last few years, my wife was looking for a cheap mp3 player, and because she had particular requirements we physically went shopping for one (because you can only tell so much by looking at specs and pictures), with the intention of buying an item that we had tried out from the shop which provided such service. IIRC, the first shop we went into is a big name in the UK, PC World. They had a row of mp3 players, but they were all in anti-theft security containers (not the original boxes, but large perspex containers) and switched off.
We asked if we could try out one of them. No, they cannot be removed from the security container. Did they know anything about the product they were trying to sell? No. Needless to say we went elsewhere.