A supermarket delivery is likely to contain frozen or chilled items. A doorperson would not be able to store them correctly until the customer gets home.
The (UK) supermarkets with online delivery offer 1 or 2 hour delivery windows so it is possible to get stuff delivered when wanted.
I don't buy ready-meals etc. I think people buying them would be less likely to use the delivery service, since it's pretty easy to stop in at a smaller supermarket on the way home and pick from the refrigerated boxes. Quicker than picking vegetables etc.
I would think the opposite, the people who care about their food would want to choose their fruit and veg at the store, people who live on ready meals would not care as much.
I used the service once, from the cheaper supermarket that offers it (Asda)
And your neighbours will be judging you for going for the low priced supermarket (as they eat their food from Lidl/Aldi)