Even if billionaires don't pay income tax and are only taxed occasionally when they sell assets, there isn't much doubt that the corporations they create and invest in generate massive amounts of tax revenue in the countries they operate. Not to mention all the revenue generated from property tax, income tax from their employees getting paid by the company, local fines and fees, sales tax, import duties, etc.
You can want the super wealthy to pay more tax when they sell stuff to fund their lifestyles, but that doesn't mean their work isn't generating large amounts of economic activity which turns into tax revenue for governments.
*if you're a billionaire
> the corporations they create and invest in generate massive amounts of tax revenue
Economic activity does generate tax revenue, billionaires generate economic activity. But if we took the billions (leave them millions, gready as they are) and spread it around it would have the opportunity to generate much more economic activity
The concentration of wealth, and the resulting concentration of income and widespread middle class impoverishment is catastrophic for our economy.
It is why, in real terms, incomes have been static for thirty years whilst the size of the economy has roughly doubled
If we can tell poor people how to behave for their own good then we can certainly help billionaires out too by taxing them back to creativity.