What does a 401k have to do with extremely rare events?

Preparing for stuff like a nuclear war would mean buying land in South America, Africa or Australia, building an underground bunker, stacking on water, food, medicine and weapons, etc.

so you buy an index fund or ETF. capture some of the positives if/when they happen, and help mitigate the negatives

some would argue performance of the 60/40 portfolio last year was an event from a tail of a very non-normal distribution

If you tuned out of current events, financial and otherwise, five years ago - in early 2018 - and your 401k was entirely on autopilot in an S&P 500 fund, it looks like your average annual return would've been about 11.5%, annual US inflation was 3.7%, and return after inflation 7.5%. Per year. You can't reasonably expect better.

And practically speaking, the tax avoidance means that's considerably better than 11% in a non-retirement account, but it was too much effort to do the math.

Despite all the pestilence, war, earthquakes, and stuff like that, doing nothing was the smart move again, with $1 or $1 million.

I don't think it makes sense to prepare for a global collapse of civilization because in the event whatever you will reap won't make hardly any difference in how much things suck. You can't eat money, much less use it as a shelter from a global rain of molten rock.

So on principle, regardless of the probability of Armageddon, I don't think one should give up much to try to hedge the end of the world.