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.
In the 80s, elementary school children made fun of K-Mart. They grew up and became customers.. presumably not of K-Mart, though.