Only the rich/elite have the time and money to run for office. Most of us are busy trying to make enough money to keep a roof over our heads and food on our table. I could not take a year off work, afford to travel to meet the people, afford the fancy clothing that is necessary to be accepted by the media , so that my name would become known, and for people to listen to what I had to say. (in most cases. There are always exceptions)
Why are there no "normal people" as presidents or prime ministers of countries? Why do they all have to be rich/elite?
Well why are they rich or elite? Look at Arnold Schwarzenegger for example. Just plain old work ethic and utmost dedication to achieving their goals. Your below average person just goes day by day, working at a meager job they don't like with no sense of what to do in the future. If you spend as much time as Arnold Swarzennegar lifting weights to improve yourself, you'd probably make something out of yourself. The successful people and the ones who achieve the most are the people willing to take risks and willing to dedicate themselves to something they believe in.
The people running for offices usually have all the necessary skills. One of the most important one is networking. The saying goes "It's not what you know, it's who you know" However I would revise it to it's "Who you know, and you knowing enough to not make a fool out of yourself" The easiest way to network with good people? Get into a high ranking University.