In reality it is a similar percentage to that of their OP, the people who live by gambling as a true profession, the rest do it for fun, but in some that fun is partly to believe that they are professionals.
I agree, it takes a lot of dedication and work to become a professional in the world of sports betting. Just because we follow the news and watch football regularly doesn't mean we know everything. This is exactly the reason why I only tend to bet during bigger tournaments. In my opinion there can go a lot of things wrong if there is no big pressure behind a game. Football players tend to perform especially well during big tournaments.