Thats a bit of a stupid comparison though isn't it? Footballers are are used up by, what, their mid 30's. They peak in their mid twenties. They are more prone to injury as they get older so the salary reflects this. The average working man (or woman) is going to earn more the older they get upto a certain point I suppose. Regardless of how many qualifications you have it will take time to learn how do a profession. A lot of the time people are paid because they know how to handle the what ifs, this comes from experience. So I'd say generally age has quite a bit to do with what you earn.