Wal what?
Fortunately, both Walmart and Kroger represent only a handful of obscure, mom and pop shops that nobody has ever heard of. Their absence won't be felt. Whew!
Safeway is pretty well known too and they just turned on contactless not too long ago. Not to mention there are regional grocers (like Stater Brothers in Southern California or Meijer in the Midwest) and small mom and pops that have it enabled. If one wants to count the "specialty" stores, there's also Trader Joe's and Whole Foods.
Like with anything credit card related, YMMV.