City centre shops (downscaled versions of the big chains like Sainsburys, Tesco) in London are almost like this today; you walk in, gather what you want and pay

City centre shops (downscaled versions of the big chains like Sainsburys, Tesco) in London are almost like this today; you walk in, gather what you want and pay using self-service check-out. There's no more than one or two cashiers but perhaps a dozen self-service checkouts. There's no interaction with anyone.