I think we have it now so it's no longer feasible to have a shop. For example, to rent a shop in Hereford town centre, not a big shop it's £20k in rent p/a on top of that the business rates are roughly the same. So £40k p/a before you've even turned the lights on. Let's say you slog yourself to death and only employ one member of staff for 40 hours per week, that's another £20,000, and you have now not even begun buying, trading, utilities, travel, accountancy etc etc etc. Small shops cannot physically make enough money to cover what owning a shop involves, it's nothing to do with Amazon, it's to do with all sorts of social and political intricacies some of which are for the benefit of everybody like NMW.
Back in the day you could rent a ghetto shop reasonably cheaply, live above it, hire a apprentice on about 10p per hour and your business could thrive, now there are wage restrictions, you often cant live where you work and everywhere is being improved and gentrified, so it's purely financial based on new social norms.