i have experienced/heard about that because i lived in Upstate NY for a summer, Buffalo (interning for Buffalo News), and spent a lot of time in Rochester (where then-gf was interning for the Democrat & Chronicle).?
Wegmans and Tops and other super-mega-grocery stores were a really big thing up there at that time and I hadn't encountered those, definitely not in the DC area, but they were vast grand warehouses of not just regular groceries but also all kind of interesting huge addendums like, big newsstands?where you?could?find the current daily newspapers from all around the world - I'd never seen anything?like that; huge stand-alone seafood department with all kinds of fresh; big cafes and such.?
And people loved those places and spent a lot of time there, they became like big community meeting places with events, i think the awful weather helped create an interest in such indoor mega-spots, and this was before the internet took over much of the centralizing/networking.
I remember articles like "Wegmans named in survey as biggest spot where spouses first met their partner" or whatever.
Along with the?competition/bad weather/pre-internet, I imagine the cheaper rent in those type of areas (Rust Belt) made it easier for the mega-stores to grow; also being able to sell beer/wine/alcohol (a lot of the East Coast did not permit that) gave them another profit incentive to innovate.
