>>There is scant evidence backing up that "usually". You obviously need some incentives for people to take risks or work hard, but no Zuckerberg or Gates or Kamprad or Ek would have been discouraged if his marginal tax rate had been 10% higher.

Had Elon Musk's marginal tax rate been 10% higher, we wouldn't have Tesla or SpaceX, considering he nearly went bankrupt multiple times trying to build both companies. Your comment about drinking water is also inaccurate considering the water systems in nearly all US cities are government controlled monopolies.