I responded to the zero sum theory in another reply.

I'll just say that every country that decided to get rid of its wealthy people wound up poorer, a lot poorer.

For a specific example, Massachusetts has a luxury yacht industry. The government decided that they wanted to tax the wealthy, and slapped a hefty tax on yachts. The billionaires simply took their yacht buying elsewhere, and the yacht industry collapsed, costing thousands of highly paid jobs. The government rescinded the tax.