Is school necessary for success?

Many millionaires success without finishing colleges or universities. For example, Bill Gats established Microsoft company, Mark Elliot Zuckerberg founded a social networking website Facebook, so on. Why do they prosper? The success is based on experience in life, not a college or university degrees. We have been educated, but we do not know how to apply that knowledge to life. Learning always comes with practice and that is the reason why the main success upon oneself. We have rights to think, to do, to select for ourselves the safest ways or to face with challenges in our future.