We're not talking about your little thousand dollars investment. We are talking billions here. 5% is really conservative when you have billions, because you don't just gamble in the market, you manipulate it and cash in the gambles of other small investors. That is how the market work. You take your thousand bucks to the bank and ask to invest it. They'll make 10% on it and give you like 2 to 3% return on your thousand dollars. If you bring 1 billion, you buy the bank. If you invest a thousand buck on the stock market, the company may give you some dividends if they succeed. If you invest one billion on the stock market, you control the company and tell it what to do. You buy and merge the competitors, split it up, you can buy the suppliers, etc...
In other words, 5% is really very conservative.