My (former) LBS owner tells me that Wiggle/CR sell lots of stuff at below the trade wholesale cost to smaller retailers.
As a country we've chosen with our credit cards and I'm as guilty as the next but, as one door closes, another opens. If you are a bike mechanic your skills are still in demand.
You were never going to become a millionaire twiddling spanners on bikes but you really only need a small rental unit somewhere. Word gets around. Maybe "Home collection/drop-off" is an option.
High-street retail has lost its appeal to me to be honest. Through no fault of their own small retailers simply can't provide the range of "stuff" that's available.
My other hobby is photography. Like any niche hobby things have changed dramatically since I were a lad. Back then Canon, Nikon, Pentax & Olympus would each have 2 or 3 cameras. A "beginner", an "enthusiast", and a "Pro", Body. The range of camera bodies would stay current for 5 years or so.
The local Cameras Shop, whilst being about 3x the size of a current Jessops, would invariably have EVERYTHING available, because they could work with many fewer models and 5 years to shift current stock.
Move to 2018 and Canon has 4 DSLRs in their "Beginner Range", 5 DSLRs in their "Enthusiast Range", and 5 in their "Pro Range". Now they have a Mirrorless, interchangeable lens, range plus countless "point-and-shoot" compacts.
No high-street shop on the planet can afford to have around 40 camera models (just from Canon) on their shelves. Multiply that by the increased number of manufacturers in the game now (Fuji, Panasonic, Sony, all competing on Beginner to Pro models) and you can guarantee that a visit to a camera shop is almost always a disappointment.
"You can get expert advice from a high-street shop".
I get 99% of my expert advice from Youtube reviews. The level of expertise available on Youtube is 2nd to none. I don't really want to know what grade of magnesium alloy a camera is made out of, but I'm sure someone on Youtube will be able to tell me.
The classic Bicycle example is the amount of Brake blocks/pads available now (Hundreds if not thousands) compared to about 3 types when I was a teen. Have they established a standard Thru-Axle or Disc mount system yet? Probably not. Just more choice, more stock to keep.
So, whilst I sometimes join in with the collective moan, "It's all just Poundshops, coffee shops, Charity shops and Betting shops", I realised a few years ago that I wasn't getting much from local high-streets. If I want a bit of retail therapy (say I want to buy a nice pair of shoes) then it means heading to a city centre. I can handle that occasionally.
Shame though.