The "UN angle"? Seriously? OK, sure. Many "billionaires" are merely people with big business empires. There's a difference between net worth and liquid capital

The "UN angle"? Seriously? OK, sure. Many "billionaires" are merely people with big business empires. There's a difference between net worth and liquid capital; the former wouldn't suffice to enact the big backup. And then there's the difference between those who chase an ever-rising number to slake some unquenchable thirst in their heads, and those who amass gigantic fortunes to enact some non-financial end. The former would never even think to try this idea, as trying to save chunks of the ending world has nothing to do with making more money. Or maybe it's merely a matter of focus -- the media hangs on the words of the likes of Gates and Musk, but Bloomberg burned half a billion to learn that you can't meme your way into political power (or perhaps just that you can't do it with an ad blitz). Anyway, I'm presuming that any individual billionaire who might be financially able to try something like this would likely also need the social capital of a Musk or Gates to overcome the boring, staid, actuarial reality that we don't have the knowledge, technology, or social capital to do something like this.