Sad part is that nearly every mid sized city has such a big complex often in the center of the city that is basically an empty shell for a supermarket in the basement.
I mean Karstadt always was the shop, that had plenty of workers running around but you would never get one that knows any of the products. I remember then not being friendly as well. And the insolvency was mostly because bad financial decisions by Schickedanz, which ie Sold buildings to a hedgefond that continuously raised the rents for the properties. 

 Yes but it worked for several decades without problems. Rents go up everywhere because of inflation. People buy less because of inflation (yes there's other factors like online sells, but there's enough people still going into shops, they just can't afford shit anymore). I don't want to judge their individual decisions but most cities are currently dying after decades of prosperity. 

 Yep. That's correct. Indeed the decision to sell property and rent it was because of financial reasons and those are I would assume 90% of cases linked to inflation. Inflation is the reason for so many problems, it's hard to comprehend.