There are many reasons to stockpile food. Having food in reserve can be a Godsend if you get laid off or ill and can't work, just eat up your food stockpile until you have money coming in again. If a major storm is heading your way and you have a good-size stockpile of food in your home, you won't be one of those people in the grocery store fighting over the last loaf of bread or gallon of milk. And if a TEOTWAWKI sort of even happens, you may have enough food stockpiled to outlast the hoards of starving people.
There are a few more reasons to stockpile food, however, that not many people think of. By buying food in bulk as it comes on sale, you can leverage the cost of buying low when something like the midwest floods wipe out major crops and send the price of some foods skyrocketing. Also, since Trump has threatened to shutdown the US-Mexico border next week, such a move could significantly disrupt food trade with Mexico and make many of the fruit and other produce we are used to buying from Mexico extremely expensive or even impossible to find during a long shutdown. Another slower moving change which could impact our food supply is climate change which could create significant, albeit not immediate, negative impacts on our food supplies.
While there is no one answer to these possible problems, stockpiling extra food is a good first step, growing some of your own food is another way to head off food supply disasters, and, like in the olden days, learning how to do without may be on the agenda as well.