Prior to the advent of online buying, a buyer had the option of buying locally, or calling a mail order outfit, usually one who advertised on photography magazines, and many of them were awful. I did discover B&H that way back in the 1980's and have bought from since. I also discovered a couple that only got one order!
Although we are a relatively small town, our local Camera store branched out into high end Audio Video and into online sales, and even opened a second store after 100 years in business. Even so, their stores do not generally keep the high end 1 series bodies or the D4 in stock, so I have to order from the warehouse if I want to see it. (I can pick it up, its only a short distance from the store) They do have a reasonable assortment of tripods, heads, and other accessories, but nothing close to what can be ordered online.
This is a typical example of adapt or die, stores that did not take internet retailing seriously and do what it took to stay in business are paying the price.
You've hit the nail on the head here.
Unfortunately for high-street retailers, a lot of sales of more "technological" devices, and this includes cameras, sports equipment (like bicycles) and consumer electronics, consumers know the part number they want, and the only differentiator is price. e.g. I know I want an EF 50mm f/1.4 USM lens, or LP-E6 battery, 5D III body, or a Shimano 105 chain. - There is no value a sales assistant can add to the sale, because I have made the purchasing decision before I walk into the store (or navigate to the site). The only factor that will change my purchasing decision is purchase price and after-sales service - e.g. I know that if I buy from Wiggle I have a local return address in Australia, and don't have to post faulty items back to the UK.
The bricks and mortar stores that are surviving are the ones that got online early and the ones that have targeted markets where the customer is looking for help to make a purchasing decision. - e.g. "I'm looking for a camera". Even the latter approach is getting thinner pickings because sites like DPReview are making it easier to choose a camera yourself if you lack in-depth knowledge. To go back to the bike shop analogy, the ones that are surviving, apart from the ones that went online, are the ones that have good workshops (who do the servicing that customers can't do themselves), and the ones that can provide a professional bike-fitting service - where the knowledge of the shop staff is so specialised that even a top cyclist can benefit from their help.
All retailers have to adapt to this trend, or die. The only ones that are being spared this at the moment are the sellers of perishable groceries (i.e. supermarkets) but even that may change.
The online business is also all about scale - which is what the likes of B&H or Wiggle have achieved. - For instance I was at a LBS recently where the assistant complained that their cost is higher than Wiggle's retail price. They just don't have the scale to move sufficient volumes to get the input costs that the big online guys have.