They overbuilt 20-30 years ago and buildings are designed to go 20-30 years between major capital expenditure. A big part of that business is syndicating and selling tax write offs... no capital investment breaks that.
So now malls are facing envelopement from discount stores and big box, plus the ever growing threat of Amazon and other e-commerce.
The malls that get investment are pivoting to supermarket anchors and entertainment.