Can these preppers survive historical situations? Real situations that have happened? Could they survive the breakdown of Yugoslavia if they were transported back in time? If you transport them to ISIS-held territory in Iraq or Syria, can they survive ISIS?

Many "total societal collapse" preppers seem to have something more akin to homesteading in mind. "How to survive long term in the wilderness without the benefit of civilization" sort of thing. Make sure to have a cache of small arms and ammo to fight off the obligatory band of three bad guys you see in the movies! Nobody is thinking about a well-equipped modern army that has no scruples about killing you. There is a reason that war zones often produce a lot of refugees.