I wonder if Dollar General, Dollar Tree, and Family Dollar did as much to kill Kmart as did Dillard’s, Target, and Walmart. I think they got crushed between the “high end” traditional retailers, and the “low end” dollar stores.
I believe they died due to corporate arrogance. I built stores for K-Mart, WalMart, Target and others. In the 80s K-Mart was convinced that WalMart was Hicks and Target was a nothing. They treated those they dealt with like you were beneath their dignity.