The article's focus wasn't oil sales per se. It's the lower priced items that Wally removed about the same time they started renovating existing stores. They have lost business to the dollar stores while focusing on higher priced items. Apparently, they have seen the error of their ways and a now bringing back many of the low priced items.
As for oil, for everyday price and selection, Wally is unmatched. Yes, when the auto stores run promo oil/filter change specials they can be competitive or beat Wally, assuming the filter in the deal is one you want to run. Also, occasionally the auto stores will run an oil only sale that may beat Wally. But, the auto stores can't compete with Wally's everyday oil prices, sometimes even with oil on special compared to everyday 5qt jug price. And, that doesn't include the Wally price match (qts.) on special at other stores.