If someone has that much money, and isn’t inclined to give it away, then there’s really only a few things they can do with it. 1) Buy actually-theoretically-useful stuff, thereby depriving others of access to those resources. 2) Save it, and maybe some of it gets invested somewhere downstream in ventures that result in a more productive economy. 3) Waste it on stuff that has nowhere near as much value as what they pay, in which case the money ends up in the hands of less-rich-than-them people while consuming relatively little in terms of actually scarce resources.
More of (2) would be better than (3), but (3) is better for everyone else than (1).
Note: This is all conditional on them already having and keeping the money. How they got it, whether they should have it, etc. are entirely separate questions.
