There's probably a lot of truth in what you say. But, the economy abhors a vacuum, and there will either be "something" that starts up, or in some cases not and those towns may die. The dead towns will have a complicated story that in many cases will probably include the death of local businesses by Walmart.

If I ran 7/11 or Shell, I might be thinking about how to put in gas 'n goes with a somewhat larger retail footprint, a larger percentage of life groceries than potato chips. That would have the backing of a large corp, so the first yearly lack of profit wouldn't kill mom and pop's retirement, and comes with knowledge of running the outlet and managing supply lines.

Bonus, you're gonna gas up before you make that three hour grocery run, maybe what they have at the gas station is good enough, or reduces the number of trips you need to make.

I'm not sure you quite grasp how hardscrabble these areas are, and 7/11 and Shell are both franchise operations in the first place. The capital still needs to come from somewhere, and gas has worse margins than grocery in the first place.

I understand the area is hardscrabble. And yes, 7/11 and Shell are franchises, that's the point. It's a response to the idea that mom and pop might not be able to step up to serve the community. That would be preferred, but if they don't, it's still possible to reduce the need for three hour drives, with a BigCorp that already knows how to do retail and already has the lines in place.

There are lots of ways to fill a hole.

>But, the economy abhors a vacuum

In theory. In practice there are tons of areas that a vacuum exists for decades.

The same way there are tons of rural communities in the US where you still can't get an internet connection apart from dial-up.

Wouldn't the people who worked at that recently closed buy'n'large store know about this?

The knowledge you are referring to was never there in the first place. Large chains have largely centralized inventory management and the actual stores are little more than distribution centers and cash tills. And, even was that knowledge and capability there, the bigger problem remains that the invisible hand doesn't make the necessary capital to open a grocery store (and both its inventory and its plant assets) appear from nowhere. This is one of the trap corners that the unfettered free marketeers of the world would pretend don't exist, but they do and they're ugly.