Option 1: Be a valuable member of society rather than a parasite, so that you can contribute something in a doomsday scenario
Option 2: Dig a big hole to live in while the poors eat each other
Option 2: Dig a big hole to live in while the poors eat each other
Plus, these options are not mutually exclusive. You can do your best to ensure a just, peaceable world while still digging a really big bunker.
The fact that we hear about Zuck and Altmann being the ones prepping or building bunkers could reflect that they are the "bad" elite, not invested in the future of the planet in the same way that Gates and his ilk are. Or alternatively, it could just be that old people don't find the idea of a survival shelter nearly as interesting as the younger generation.
The one thing I genuinely wonder is what odds each billionaires gives their private mercenary force for not usurping the “throne” from them after an apocalypse.