On top of that Americans pay more healthcare related income taxes than anyone else! Those could well be used to cover the expenses of a socialized system. It’s absolutely amazing that people think they don’t need it.

What makes you think that a global crisis would reduce humanity to tribes and clans? Isn’t it more likely that desperate times result in something more like a global government and more systematic enslavement of humans? How could the owning class ever pass on the opportunity of not having to work and instead utilize their workers as efficiently as possible?