Please provide a list of all multi-billionaires who have somehow managed to lose any significant portion of their wealth outside of a divorce combined with bad marriage planning. And even in those rare cases, they don't approach bankruptcy.

It isn't that they get bailed out by the government (like the banks in 2008), it is that at the scale of their wealth there is no realistic way to lose it fast enough to make any significant negative difference when the neutral state of wealth at that scale is to snowball ever larger (mostly because we refuse to tax it appropriately).