So let's say the world goes to hell in a handbasket... Civilization burned to the ground. Dog and cats living together, etc.
I hear this a lot from anti-gold people. Yes if the entire world civilization collapses and 98% of humans on earth die, then gold will be worthless. However I would point out that such a scenario has never happened in all of recorded history.
I'm not saying a worldwide apocalypse is impossible... of course it's possible. It's just very unlikely. A far more likely scenario is a local collapse of civilization, like a famine and civil war in Middle East or a governmental collapse/economic ruin in South America or Germany getting frisky again and getting bombed into oblivion by Russians/Americans.
Such local collapses (local SHTF in survivor speak) have occurred many times in history, some quite recently. And in all such cases, gold has never become worthless. In fact gold has been the gold standard of stored wealth.
As long as there is civilization somewhere that people can hope to escape to, gold will be what people will expect to hold value.