The thing with shops is that they thrive when there are lots of them as a street full of shops attracts customers. Trouble is the rot sets in and then they tend to close, one by one, until you're left with the charity shops and Turkish Barbers.
My parents had a newsagents shop on a parade of several shops, including a greengrocer, grocers, butchers, chemist, hairdressers, bakers, off licence, post office, hardware shop. Over the 20 or so years they owned the shop, the parade went from a vibrant parade to our shop being the only one left open, which we had to close once we got a sodding huge Asda less than a mile away. Drove past for the first time in over a decade and it's now a dodgy looking ethnic convenience store, a Turkish Barbers, a couple of charity shops and a nail bar!
What started the rot was the closure of the butchers shop - the guy retired and couldn't sell it. Once customers weren't coming for the fresh meat, they went elsewhere for their meat, so weren't buying groceries or anything else as they'd get everything at the next nearest shopping parade. And then, one by one, all the other shops closed too due to lack of footfall.
In the town I live now, there was another parade that seemed to survive pretty well. Until the council "traffic calmed" it, by narrowing the road to put in pedestrian islands, speed ramps, double yellow lines, etc., which instead of "revitalising" it as the council planned, it killed it stone dead, which is, again, now just ethnic convenience store, Turkish Barbers, charity shops etc.
So it's not just supermarkets killing off small shops, it's stupid council decisions too!