I don't think this is realistic or possible for most cities/supermarkets. Home delivery is great but not available for the overwhelming majority of people, and personally I think people who are vulnerable, disabled, etc., should have priority here, not me... able-bodied, healthy, a lower-risk than an elderly person.
A pre-shopped pick-up is more realistic, but not entirely so... Our supermarkets just aren't equipped to handle the volume. They have 1 cooler-locker up front with the "preshopped items," but it's small... like... I dunno maybe a 10-foot long cooler locker that can hold maybe a dozen grocery orders. It's just not possible to accomodate all shoppers there.
I think we're going to have to live with the system that's in place now, and supermarkets are going to have to respond to potential staffing shortages by paying more. If they doubled+ pay ... say, to $20/hr for supermarket workers who were most at risk (checkout people, baggers), then they'd have a lot of people applying, especially as unemployment is skyrocketing.