Scandinavian countries have high taxes and a high GDP, same is still true for Germany. Many low tax countries have terrible GDP too, so it's not the tax. And

Scandinavian countries have high taxes and a high GDP, same is still true for Germany. Many low tax countries have terrible GDP too, so it's not the tax. And businesses needs customers. More middle class customers support more businesses than few billionaires. If you spread the wealth it benefits the economy and helps creating new businesses. Companies like Airbnb, Uber, Netflix etc. don't satisfy a need of billionaires. So you either can hope a billionaire founds a useful company or give wealth back to the people and let the market do the choosing.