This is trickier than it might seem. A yacht is actually an asset! (Albeit one that depreciates quickly and has enormous running costs).

Practically everything a billionaire could spend money on "at scale" is just another asset. Although again, "yacht" is a terrible asset class.

To actually get rid of enormous wealth you have to either waste it (throw a huge party? own assets that depreciate a lot? shoot it into space?) or give it away somehow.