I'd be perfectly content with this model, but the problem is then they'd have to hire employees to do things! Stores would much rather have us pick everything ourselves, checkout ourselves, and have our cars remote detonated by robots automatically if the crime computer deems it appropriate.

That way they only have to hire two employees. One to drag carts around the parking lot and one to drag keys to all the locked cabinets of soap and shampoo and diapers and whatnot.

The main issue is spiky demand, you’d have keep a cadre of employees around to minimize peak latency. Offloading tasks to the shopper scales well with usage.