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.
A town is a bit more than that, but it is how towns typically began, from a central trading place and nearby settlements. Only this is a planned concrete parking lot and established chain along with fully built domiciles, already in a city/town’s jurisdiction.