In New Jersey, I think the downfall of some of the malls has to do with increased public bus service to the malls. When I was growing up, Moorestown was a fairly upper-class mall, serving the relatively wealthy people in the area. Then I remember hearing about how the bus service was going to be increased from Camden, "bringing in additional revenue". What it brought it was an undesirable element. People from Camden are not like people from Moorestown. They're usually dressed like thugs, strutting around the mall like they're limping, being loud and obnoxious in an otherwise calm place. What made it really bad is that when you go in the side entrance, where you used to have kids hanging out (making it a popular spot) you now had a bunch of Camden people standing around outside waiting for the bus. I personally didn't want to be around such filth, so I stopped going for the most part, just as others did.
Soon the place started to go downhill. The more wealthy people chose to go elsewhere, they didn't want to be around ghetto people. Now the mall is only a fraction of what it used to be. It used to be much nicer and cleaner.