In North America are non-supermarkets and non-warehouses even 5% of grocery retail? I think that restaurants being allowed to sell groceries would've been cool. But I don't see how mom and pop grocers move the needle at all here.
But in smaller towns in North America it's getting rarer and rarer to see even an independent butchery, let alone veggie market or bakery.
At least one restaurant chain already is:
https://www.houstonchronicle.com/neighborhood/tomball/busine...
At least 2 restaraunts in my town do this. Order online, drive around beck (sometimes with a line of cars, but never more than a 5 minute wait), and they drop your food/tp/etc in the trunk. Much better than hitting up Safeway or Costco, and not really much more expensive.