I have the same experience. I am probably upper middle class (whatever that means) and my kids, as well as my wife like dollar stores. Whenever we visit one I also end up buying at least $10 of random stuff myself (jigsaw puzzles or light sticks or toys to hack).

While I do not dispute the fact that many folks, especially in rural areas are very tight on money, the argument that Dollar Tree cannot be successful without rampant poverty seems unproven.

Just a single data point.