I don't think that is true at all, there will be towns with literally no shops whatsoever. Jessops had too many branches losing money, and they could not stay afloat supporting them all, so all of the very profitable stores also suffered.
You only have to look at things like specialist Hi-Fi stores to see that there is room for at least one in big towns/small citites etc.
But Pros and even Serious Amateurs clearly weren't using Jessops. They were either buying online or using a good independent they know of.
If people in towns were regularly ordering upmarket lenses and pro cameras, then they would have kept stock of some in the store. Clearly though, people weren't, so thats why only Jessops in cities were likely to be carrying a better selection of kit.
So for regular point and shoot type cameras, there is no longer the boom there that there once was. For Pros they didn't really carry the gear. For the market of people interested in Photography getting their first DSLR, they couldn't compete with the big online retailers on price.
I personally don't think you see much in the way of many specialised Hi-Fi stores these days, sure you get some some independent ones here and there, like good camera shops. However its really only Richer Sounds you tend to see about the place and they are more about flogging TVs these days compared to being audiophile Hi-Fi experts, but then that just reflects the changing nature of markets.
Would you rather buy the item you want in a shop?
Or would you rather buy the same item significantly cheaper, delivered to you at home, protected by distance selling regulations and still the full warranty.... I think you will find most people go for the second option.
I am sorry that Jessops is gone, but I wasn't buying anything in there. I even live in London where I am spoiled for decent independents and I still tend to buy online.