Imagine apartments built into what used to be department stores, (Oh, you’re JC Penny 203? I’m at Sears 106). Get those old arcades up and running. Set up meal stations at the food court. Once people actually live there, stores will start to move back in.
If I’m unable to finish my life in my own home, that doesn’t sound like a terrible option.
And walking down to the food court to use a bathroom may be, ahem, problematic for a retirement community.
There was a dead mall in a nearby city that was finally bulldozed to make way for apartments. It’s taken decades and nowhere near habitable yet. Sort of a start though.