Just because a store has 'dollar' in its name doesn't mean it's a dollar store. Dollar General in particular is not the kind of store where all or even most things are a dollar, which was the traditional meaning of 'dollar store'.
At least your own source notes this: "And despite their names, many dollar chains, including Family Dollar and Dollar General, sell items that cost $10 or more. Dollar Tree remains the only major retailer that continues to price its entire inventory for $1."
I shopped at a couple Dollar Generals on a road trip this past summer (it was interesting to see how many towns we passed through had one, as opposed to some other brand) and it seemed to me like a scaled down Fred Meyer, or a super scaled down Walmart. Maybe a scaled up gas station? And that's fine for most people, as evidenced by their market success. They tend to stock the same popular stuff as a bigger grocery store would. But you're not magically going to pay $1 for your full sized frozen pizza just because of the name. Indeed I can see an ad advertising two-for-$8 Tombstone pizzas, which is about the same as routine sales at my local Safeway in the rich Seattle area.
(And an edit for your edit, you're vaguely complaining that something is wrong for the subset of people where such stores are the only option, as if shipping and delivery don't exist, but whatever, you want them to have no options? I know you probably don't but it'd be more constructive to articulate what you actually want.)