It doesn't have to be an either/or situation, you could integrate mobile shopping with town centres by letting people buy online and pick up from the shops; would often be more convenient for the consumer than having to wait 24+ hours, and be at home, for a delivery, and for the shops it gets more footfall in the area, people will stop by for food/drink or do some window shopping.
If I had the first idea writing apps/product inventory stuff, I'd do it meself and become a millionaire... but I don't. So if anyone off here does it, just chuck me a few bob, thanks