Wealthy people don't consume in the way you understand consumption. Wealth, at the higher levels, is almost synonymous with power. It's what amplifies your agency. By owning large organizations, investing in new developments, starting new organizations, controlling organizational output (think media companies in particular), wealth is converted into control over people and to a certain extent, governments.

Wealth gets "consumed" by bad investments. Those "bad" investments might even be considered as expenditure, almost as consumption, by the wealthy, e.g. subsidizing a newspaper - but what does sales tax (or some other consumption tax) look like when it's applied to journalists' salaries? Doesn't really make sense, does it.