Agree entirely, crude footwear could be manufactured locally in or after any long term disaster, but would be far inferior to that which can be purchased cheaply at present.

The making or mending of footwear is very time consuming if done by hand, and therefore expensive.

I keep 10 pairs of unworn shoes to hand and several pairs of boots. The shoes that I buy are cheap and dont last that well, but ample stocks allow for replacements.

Shoes that have holes in the soles can sometimes be repaired simply and if not watertight can be reserved for indoor or dry weather use.