A prepper is an individual or group that prepares or makes preparations in advance of, or prior to, any change in normal circumstances.
The video below discusses how dependent we are on foreign entities for food, gas and other things essential to living our lives and points out "how fragile the supply chain really is."
We go to the grocery store without thought of where the food comes from. We pump our gas into our vehicles without thinking where the gas comes from originally. Everything is here for us, the internet, food, water, communications via computer or phones, a host of technology that most of us are unprepared to survive without.
The video does bring about the question, if the economy collapses, who is ultimately capable of surviving the chaos that will ensue?
It doesn't even have to be an economic collapse, other examples could be a cyber attack that knocks out the internet therefore all our services, or if we are attacked by another country resulting in the same, plenty of examples are out there of situations that would leave the majority of us vulnerable and completely unprepared to survive.
Their answer is in the title of the video "Economic Collapse Approaches Preppers Shall Inherit the Earth."