> I've seen nothing to that effect

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.