Rich people are only smart insofar as they buy brains to think for them. The truth is that most economists and finance "experts" have really no clue how anything works, except for within a narrow paradigm which is the non-decaying period of capitalist exploitation.
The reason they are buying islands, bunkers and stuff is more of the essence that so is their primary stratagem: buy things you want, buy things you might need and buy contingencies to make potential problems go away.
Cannot find any source on this. Do you have a link?