Maybe. It depends where you live, though--not every area is capable of sustaining its own food supply(1). And, even those that are still import some goods.

But I think we're shifting the discussion a bit to a "Long Emergency" scenario.

As a bit of localist, I'm more troubled by local governments who bend over backward to bring large retailers into an area. I think these more localized benefits (tax breaks, development dollars, etc) are far more beneficial to, say, Wal-Mart, than the highway system.

(1) And many that can have transformed that land into housing and strip malls.

EDIT: Fixed formatting.