Small towns and rural communities typically lack a national chain grocery store.
The dollar stores fill the gap.
I read an article in the past few weeks describing how these dollar stores put a lot of small family supermarkets out of business - and the loss of those left small communities without any fresh produce (contributing to “food deserts” for white people). It makes sense, though I don’t see these places as bargains - generally lower prices are due to smaller packages/sizes. They have some in my area, but they don’t really compete with the large supermarket chains - two different clienteles. I’ll only go in for one or two items I need in a pinch; they are understaffed, and don’t offer the variety a real supermarket offers (outside of the deli/produce sections, which they lack altogether).
A bigger threat to our supermarkets are the Wal-Marts with full supermarkets, though I can’t go into one of them after 8 am; living between Newark and Jersey City, our Wal-Mart fills up quickly.