I have to admit I don't know much about these delivery services: how much they cost, is there a minimum spend, do they really deliver anywhere or only to urban areas?
Anyway, in principle yes, I think it's a good system: you buy your weekly shopping this way, which means you don't need a car for shopping. If it is a realistic option, then one less excuse for rural (or at least semi rural and suburban) dwellers to complain about how they just can't survive without a car.
Local shops can still have a role to play in providing the odd items you need more regularly or at short notice (albeit at a slightly higher price). In a system with lower car ownership these kinds of shops will be viable and will function just like they do in properly urban areas.
So, thinking about it yes, online supermarket shopping with home delivery is probably a realistic way forward, and would become a more popular option if we up the costs of private motoring.