It's not clear to me what the problem is that the article is outlining. The Dollar General near me has the exact same brands as you would find in any larger retail establishment, they just have found a way to stock the 80% that folks typically need. They are filling a niche between the gas station convenience store and traditional grocery/big box retail. They don't have a produce section, just a bit of fruit. Is that…
Dollar Tree is an actual "dollar store" where literally every item costs $1. Dollar Tree's items are generally no-name discount brands that wouldn't be found in big grocery store chains, or familiar brands in unique very small packages.
Dollar General, at least in the two parts of the US I've seen them in (areas of California and the Midwest), is as you describe: something between a convenience store and a traditional grocery store sans produce. They have all the normal big brands: Oreos, Doritos, etc. in the normal package sizes at what seemed to me to be normal grocery store prices.