Spanners wanted (mechanics)

Remains to be seen whether the running shop will be viable long term.
Bricks and mortar high street retail is dying, online retail rules over all.
Prohibitive costs for bike shops on terms of rents, business rates, staffing, training of staff, product (especially if you have to stock bikes and lots of them) when all customers see internet pricing as the going rate means that most bike shops can't be run efficiently enough to make a profit. And if they do make a profit it's so slim as to be non-existent.
Distributors have not moved with the times either, systemically handicapping the service that bike shops could provide to try to match online retail service (small goods carriage items from suppliers generally incur anything from £5-£12.50 for a single item; true next day delivery is not universal; weekend delivery that isn't charged at an exorbitant rate is almost non-existent). Distributors are only interested in selling bulk really, so independent bike shops are treated with disdain. Everything will move online eventually, the only bricks & mortar edifices that remain will be bike workshops/service centres and destination shops designed for urban hipsters who want the "experience".

How can a retailer selling running apparel more viable than a bike shop?

Running is the new cycling?

It's the same company that runs Cycle Surgery. It encompasses Cotswold, Snow & Rock, Cycle Surgery and Runners Need.

Running shops are profitable simply because it's cheaper and people tend to wear out stuff quicker.

The dynamic for brick and mortar stores has to change. Buying habits dictate purchasing power, which is also locked to manufacturers and retailers.
Do people still buy bikes? Yes. It's just not as wanton as it used to be. The more human retailers get the more the possibility for survival.

I can't speak for where I work as I have near enough zero influence over the direction said company takes, but the closing down of stores is multi faceted and isn't exclusive to cycling.

The reasons are numerous and require a proper chat. @t_w has gone into it somewhat regarding bike shops, but I don't agree that all that will remain will be workshops.

The vibe I get is that people still like going into bike shops, it's just most are either fucking boring, elitist, or 'optimized' into oblivion so people treat them as such.

tldr. Brick and Mortar isn't shit, it's just how they're run and forced to run makes them so, whether that's a death knell remains to be seen.

If I am not mistaken JD Whiskers used to be round the corner from West End Lane.... many, many moons ago.