His research suggests that wealth inequality has been driven by asset appreciation, most recently the stock market. Not too long ago it was driven more by real estate value. Many super wealthy people are rich because of business wealth, stocks. Most middle class are wealthy because of house/real estate prices.

Bonus up front and risk losing it later if poorly performed--that condition generated better outcome than...Bonus at end only if performance achieved. So fear of losing bonus already given at start is better incentive for preforming than giving bonus at end only w/ good performance.