It became really clear to me during my 180 days in the wild that when surviving in a small group some modern tools can have a great impact on a survival situation. A force multiplier is something that increases the effectiveness of an individual or small group; in this case it multiplies the ability to fulfill our basic needs in the wilderness.
Living indefinitely in the wilderness, alone, using just a few or even no modern tools is a myth. Hunter gatherer ways of life relied on tribal organization with divisions of labor, and plenty of helping hands.
There are just not enough hours in the day for one or two people to build their own primitive arrows, hooks, and nets, and then hunt, fish, gather, and trap. There are few people that could attempt this and few locations where this could be done.
Nevertheless there is gear that would be a force multiplier for survival in a long term scenario:
Making and maintaining a fully watertight roof out of natural materials can be very difficult and labour intensive. That time and energy could be spent gathering firewood or food. Water always seems to find a way through roofs made of natural materials anyways. Tarps are lightweight and can be transported easily in case you want to move your camp. Sil-nylon tarps are not cheap but they are super light and are fairly durable if properly cared for. Tarps are just an essential item to have in long term survival.
In areas where bugs are a serious issue, like the boreal forest, having some type of bug shelter is needed for sleep. A lightweight 3 season tent for two people provides protection from ticks, horseflies, mosquitoes as well as rain. Being able to consistently have a good sleep, undisturbed by bugs, is a game changer.
Clothes are one of the most important survival items. They are very difficult to improvise in the field, and are your first layer of protection against the elements, which is the most common survival threat. A good set of outdoor clothes that can be layered according to different weather conditions is a force multiplier. Being outdoors with inappropriate footwear, particularly in freezing temperatures, can be a quick reality check. Rain gear and warm clothes will make your life easier in a survival situation. Being warm and dry means that your body will use less energy keeping itself warm.
Being able to sleep warm without gathering firewood and maintaining a fire overnight is extremely important. Efficiency means survival and the more energy you can save the better. In cold areas a sleeping bag is one of the most important pieces of gear. It should be made of synthetic insulation if used for a long time, due to moisture build up, and it should be rated to the coldest temperature to be encountered. A high quality synthetic sleeping bag is worth its weight in gold; in a survival situation they are a game changer.
Most people that know how to start a fire with friction carry a lighter. It just makes sense to have easy, simple methods of starting a fire. Either a lighter, or a ferro rod are good long term fire starters. Fires are just a no-brainer in wilderness survival.
Axe, Machete, Saw
Choose one or more. These tools along with pots where among the first tools traded by indigenous peoples for a reason, they are very effective survival aids. They make gathering firewood easier and can be used for shelter building.
Hands down this would be one of the most valuable food procurement tools if there are fish holding streams in the area. Off-shore industrial fishing with nets is so effective that many populations of fish have collapsed. Gill nets are passive means of gathering food and can work 24/7. Casting nets could be a better option for coastal areas.
Fishing rod and hooks
Fishing rods allow you to actively hunt/trap fish. They complement other passive fishing techniques. Modern fishing rods paired with lures or bait can be a very effective way of catching fish, and I believe they are a must in any decent long term survival kit.
Hooks are light and compact; they are not easy to replicate in the wild. Good hooks are super valuable, when I was living in the wild, I couldn’t afford to lose a hook. This is one object where quantity really matters.
Metal pots are a game changer in the wilderness. They allow you to collect water and treat it, and to cook food in a way that preserves the most energy. Some pots can also be used to store food overnight protected from rodents.
A .22 rifle can be used to hunt small and even large game in a survival situation. Bullets of .22 calibre are cheap, light and compact, meaning you can carry much more than any other calibre. Hunting a few medium or large game could be the difference between making it through the winter or not.
Body grip steel traps are a simple way of trapping medium game for sustenance. This traps don’t need to be baited if used in a well used, funnelled trail. They are very durable and easy to use.
A bicycle or a canoe allow you to bring more equipment and supplies into the wilderness. Other ideas for vehicles are packrafts and kayaks. A canoe can also be used to gather firewood from places far away from camp for instance. They are exceptional aids in fishing. A human-powered vehicle can increase your roaming area and thus increasing your access to hunting, trapping, fishing, and harvesting grounds. The time and energy saved from using a vehicle can be better spent procuring food.