It’s willful negligence on a societal scale. Any billionaire with a bunker is effectively saying they expect everyone to die and refuse to do anything to stop it.
It makes one wonder what they expect to come out the other side of such a late-stage/modern war, but I think what they care about is that there will be less of us.
Ultimately they just want to widen the inequality gap and remove as much bargaining power from the working class. It will be very hard for people not born of certain privileges to climb the ranks through education and merit, if not impossible.
Their goal will be to accomplish this without causing a French Revolution V2 (hence all the new surveillance being rolled out), which is where they'll provide wars for us to fight in that will be rooted in false pretenses that appeal to people's basest instincts, like race and nationalism. The bunkers and private communities they build in far off islands are for the occasion this fails and there is some sort of French Revolution V2, not some sort of existential threat from AI (imo).