I think some Marple traders make the trudge a pleasure. Saturday mornings are fun and it's good to potter, but for convenience and price you can't beat a supermarket. And when you've got 5 kids, pottering isn't always an option.
Why would anyone elect to trudge through mud and sleet wearing fourteen layers of clothing to shop at establishments who - if they actually had what you needed in stock - would charge you more for it than say Tesco or B&Q? The idea that the average High Street proprietor is more knowledgeable about his product or more concerned with satisfying his customers is, frankly, balderdash!
Customer service is universally bad, and the only place to get decent advice on
product is on the Internet - specifically from other consumers.
But I suspect the truth is that they fear that the majority of people do actually want the convenience and economy of a supermarket. So what these self-styled 'community activists' are saying is that townsfolk must be forced to shop in the High Street for its preservation and, apparently, their own good. This is a mini fascism.