"When I've gone locally, the stores are pretty bad. The stores are dirty, inventory is on the ground, lines are long, employees do not seem happy"

It depends on the store. More specifically, it depends on the customer demographics of the store. This applies to Dolar Tree also.

We regularly go to these stores within a 50 mile radius. When I say "we" I mean that I drive and my wife goes in and shops. I wait in the car, read a book, and pop the trunk when she comes out.

Certain demographics are not bothered by dirty stores and inventory piled up in boxes in the aisles. As I've seen it, "inventory is on the ground" means that the store has gotten a truck delivery and doesn't have empty shelf space to put the stuff. Go back a couple days later and it's all gone. I recall once going in and they had 2 pallets of power strips in the aisle. The price was good so I bought 1. A few hours later I decided that I should grab 2 or 3 more. One pallet was empty and the other has half gone.