They must have gotten their economic degree from Scrooge McDuck university where rich people keep all their money in a vault so they can sit and watch it all day. That is fine in comics but not so much in the real world.
In the real world wealthy people invest their money as well as buy expensive things. Their money is used to employ millions of people (and that is the trickle down).
When the tax rate is too high, two things happen, the wealthy find ways to decrease their taxes and the government waste the money they take.
No nation in history has ever taxed them selves into prosperity (read somewhere but forgot where).
Yes! Saved money is invested money in the modern economy, like it or not.