Because they fancy that they'll be fighting a war and not have time for sleep, they'll steal water and food, and really only need to get to the small stream 1 mile down the road. Plus, you have to buy surplus gear, because it's always in OD green, which far surpasses high tech gear. You buy 'survival' supplies on the cheap, so you can drop $3k on guns and ammo, because when the local mountain erupts, the power outage hits, or a earthquake occurs, you must FIGHT and KILL. Mankind has no ability to work together, you see. Regardless of the repeated occurrences where communities band together to help each other, charities show up to provide aid, and pleas go out for food, water, first aid supplies, blood, and warm blankets and shelter, that will not occur the next time. We are all doomed, so better to carry a 10 lb shovel that you can beat a skull with than 50 Clif bars and water.