> You've gotta be referring to escalators here. Never seen a moving walkway in a big-box store

I have seen some occasionally in stores, in or around Paris. They usually are on an incline to allow trolleys to be taken up or down a level. Or similarly outside malls to get trolleys to the upper level of a car park. That’s in places where you have to stack car parks instead of just having them sprawl all over the place, of course.

> or a subway station for that matter.

There are a few of them in Paris métro stations. Some of them in the London Underground, as well.