The physical shopping radius for a specialty shop is also a lot larger than a generic store.
If you have the store to find mid-century burnished widgets at, people might regularly come from a hundred or more miles away when they really need just the right sort of widget, and when they do -- if your stock lives up to the hype -- they will tend to be big customers, buying a lot (since they weren't casually dropping in), being fairly price insensitive (since they have few alternatives for what they need), and repeat customers (since you seldom end up needing a specialty item once).
You might still need an online storefront, or you might take phone orders from your regulars, but the clientele of a specialty shop is radically different than the clientele of a generic shop, which relies more on people wandering by and which competes with ten other stores a mile away, and the big box store off the highway.
I think this is exactly it - these stores are now perfect fusion of small online store and small offline store. If you order something online the owner picks it off the shelf and puts it in an envelope - and the online shop can drive traffic to the physical one.
