I checked Tesco when posting, and could get a late evening delivery slot on Saturday. Collection I could get 7am Saturday morning. Not saying the system is perfect, but it's definitely possible to get next day delivery on groceries. Even Amazon doesn't guarantee next day on everything after a certain time, and I see this as much the same - you snooze, you gotta wait an few more hours.

I am interested in a deliveroo/just-eat style grocery shopping solution though. If the store can pick and pack your order in 3 hours and put it at the front of the store for collection by a group of drivers that are constantly in rotation, how is that any different from collecting my takeaway and driving it to my house? It really isn't, but it's also not an urgent operation that needs such a quick turn around time IMO. I'm sure others will pay for the convenience, but I'm personally happy waiting 12 hours and collecting it myself so long as I don't have to step inside the store.