Survivalists' concerns and preparations have changed over the years. During the 1970s, fears were economic collapse, hyperinflation, and famine. Preparations included food storage and survival retreats in the country which could be farmed. Some survivalists stockpiled precious metals and barterable goods (such as common-caliber ammunition) because they assumed that paper currency would become worthless. During the early 1980s, nuclear war became a common fear, and some survivalists constructed fallout shelters.
Astronauts are provided with survival kits due to the difficulty of predicting where a spacecraft will land on its return to earth, especially in the case of an equipment failure. In early US space flights, the kit was optimised for survival at sea; the one provided for John Glenn on the first American space flight in Friendship 7 contained "a life raft, pocket knife, signaling mirror, shark repellent, seawater desalting tablets, sunscreen, soap, first aid kit, and other items". A survival kit was provided for the Apollo program which was "...designed to provide a 48-hour postlanding (water or land) survival capability for three crewmen between 40 degrees North and South latitudes". It contained "a survival radio, a survival light assembly, desalter kits, a machete, sunglasses, water cans, sun lotion, a blanket, a pocket knife, netting and foam pads".
You now have a foolproof method of navigation and enough light. But you need to sleep and eat. The Gerber Bear Grylls Ultimate pro knife with its full tang 4 ¾” high carbon steel blade is just the piece of survival gear you need to help you harvest materials for an emergency shelter, get a fire started, open cans and if necessary, dress wounds and cut bandages.
Lastly, there are no “EXPERT” preppers that I know of! Just as there should be no one directing, suggesting or quantifying anyone’s efforts toward being ultimately prepared. We are all in different stages with any of the attributes required to be our best, not someone else’s best. There are just way to many factors that have to go into the equation for one person to know it all. I learned a long time ago to never point out a problem without recommending a solution. I feel survival training through this venue is best served by not casting doubt, mistrust and pointing out scary gaps in plans being worked on. Instead, Train skills, knowledge and attitudes. The “How Tos”, “Where to Find Useful Info” and just the considerations of the attitudes. Let the individual prepper decide how it fits into their specific plan.
Another wave of survivalism began after the September 11, 2001, attacks and subsequent bombings in Bali, Madrid, and London. This resurgence of interest in survivalism appears to be as strong as the 1970s era focus on the topic. The fear of war, avian influenza, energy shortages, environmental disasters, and global climate change, coupled with economic uncertainty and the apparent vulnerability of humanity after the 2004 Indian Ocean earthquake and tsunami and Hurricane Katrina, have increased interest in survivalism topics.
Articles on the subject appeared in small-distribution libertarian publications such as The Innovator and Atlantis Quarterly. It was during this period that Robert D. Kephart began publishing Inflation Survival Letter (later renamed Personal Finance). For several years the newsletter included a continuing section on personal preparedness written by Stephens. It promoted expensive seminars around the US on similar cautionary topics. Stephens participated, along with James McKeever and other defensive investing, "hard money" advocates.
For global catastrophic risks the costs of food storage become impractical for most of the population  and for some such catastrophes conventional agriculture would not function due to the loss of a large fraction of sunlight (e.g. during nuclear winter or a supervolcano). In such situations, alternative food is necessary, which is converting natural gas and wood fiber to human edible food.
With the world seeming to become a more volatile and dangerous place with every encroaching year, it can be hard to know exactly where you can feel safe. The modern media is overloaded with stories about violence, crime, and sensational pieces on the worst people in our society. But there have to be some places within the United States where the chances of anything like that happening to you is next to impossible, right?