Yeah DG operates with a really low headcount.
Their business model is mini WalMart with even lower costs.
I think they succeed where their location is favorable.
They already have about 11,500 stores (ref: 14,500 McDonalds, 12,000 Starbux)
I don’t find their prices very competitive (in the same manner as Wal-Mart, where you can find a great price on the same brand/size of products). Many of Dollar General’s items seem to be a smaller size, and their store brand isn’t very good (bread, for example).
The low headcount makes buying the smallest thing there a pain in the rear; in my area they are convenient only by being a few blocks closer than Foodtown (which costs more money but much less time).