[prostoalex]

1) The set of people who have access to venture capital through pension funds is smaller than the set of people who have access to public stock market.

2) Historical figures of stock market performance include such breakaway successes as MSFT and AAPL with the stories of "if you bought 100 shares of X on the day they went public, it would be worth [high dollar amount] today". Remove the outliers responsible for such gains, and general public will respond by removing liquidity from public markets until it becomes more attractive.

3) Things like DJIA and S&P 500 for better or for worse are viewed as proxies of US economic health, and are frequently used as underlying metrics of investor optimism, etc. Flatter indices are boring and are frequently interpreted as "going nowhere".