Earlier quoted context omitted.
What kind of "basics" did you find missing in actual grocery stores, and what were the actual stores in question?
Not GP, but I can offer: real cheese (not squares of individually wrapped plastic, nor grated and mixed with whatever to prevent caking), Walmart.
https://www.walmart.com/ip/Great-Value-Block-Sharp-Cheddar-C...
https://www.walmart.com/ip/Great-Value-Low-Moisture-Part-Ski...
https://www.walmart.com/ip/Frigo-Parmesan-Cheese-Wedge-5-oz-...
https://www.walmart.com/ip/Tillamook-Medium-Cheddar-Cheese-B...
https://www.walmart.com/ip/Great-Value-Swiss-Cheese-Block-8-...
https://www.walmart.com/ip/Dutchmark-Smoked-Gouda-Cheese-7-o...
https://www.walmart.com/ip/Castello-Gourmet-Creamy-Danish-Ha...
https://www.walmart.com/ip/Kerrygold-Grass-Fed-Dubliner-Iris...
and on and on and on and on and on...
It might not be right next to the pre-shredded cheese (usually those house brand blocks of cheddar and what not are), sometimes they're in a fancier part of the deli area. But I can't think of a time I've gone to a Walmart looking for a block of cheese and not found any cheese.
Its not going to be the fanciest varieties, but once again the question was for "basics" that don't exist. Having cheddar, swiss, parmesean, gouda, etc. is having the basics.