Does Walmart or Target not deliver? In the UK all the large supermarkets (Tesco, Sainsbury's, M&S, Asda) let you order online and deliver to your house. They actually just get someone to go round a supermarket and pick the stuff off the shelves.
Online grocery shopping is more developed in the UK than any other major market. A large part of it is the London effect where you have a large number of middle-class shoppers who don't have cars in close proximity to each other, that makes the economics vastly better for the supermarkets.
Perhaps, though I know Oxford also has home delivery so it's not just London. I've not understood how Oxford could have it but San Francisco doesn't.
Safeway has done home delivery since at least March, so it's not an unknown service here in the US.
That's true to an extent, but I've also had deliveries from supermarkets in incredibly rural areas whilst on holiday, once to a farmhouse which was so remote you couldn't see any of the neighbours.