I am going on the assumption that fuel and gas power means of transportation are extremely limited or gone.
Primary means of transportation is human powered, foot, bicycle, etc.
I have a large Amish community in my area, and a few people with horses, but that is the exception, not the rule. And your average American would not know how to ride a horse, let alone care for one.
Having said that, humping around with all that gear is cumbersome, tiring, and will require the consumption of more water and calories.
As James said, it does have its place. Just not sure how much in a post-SHTF situation.
Not sure where the idea of concealed carry came from in a post-SHTF situation. If ROL is gone, why bother concealed? I can just as easily imagine everyone open carrying and thinking nothing of it.