Walmart, Autozone, Advance, any auto parts store, etc., anywhere oil filters are sold. 0w-20 is the same oil regardless of where its sold. Same with oil filters.
Actually your statement is rubish. ANY 0w-20 oil is satisfactory in ANY car calling for 0w-20 and meets the specs set forth in the owners manual, that is a fact. Further it makes NO differace where the oil is purchased. Walmart, Kmart or whatever.This statement is complete, total, and utter rubbish.
API rated 0w20 will have to meet common specs, but different oil have different additive packages and properties.
Not all oil filters are made the same way either, differences in media material, bypass settings, amount of media, overall construction, etc.
So, in other words, WRONG.