You don't have to believe that a catastrophic disaster or emergency is likely to occur in the future to make preparations for it. Creating a sustainable food supply is something that most of us can do in a smaller space than one would usually imagine. Expanding that space and choosing wisely the foodstuffs we choose to grow allows one to turn our preparations into profits.
In Prepping for Profit, author Dale Bannock gives detailed examples and suggestions for preparing for an unseen disruption to our food supply. Furthermore, he offers proposals for channeling our efforts into growing non-typical items into highly profitable commodities. As a bonus, projections for a self-sustaining urban farm are outlined in the last chapter as an example of how "one man's trash" can truly become another man's treasure.
There's no agreement among preppers about what disaster is most imminent, just that one will come.