That's why most of bettors always lose, even though many people say it's a skill based game, but it's still not enough to give a higher guarantee the gambler will win and beat the house.
As much as I agree that some types of games that are considered gambling are actually skill games (namely poker) I wouldn't say the same thing about sports betting. Sure, if you have good analytical skills and knowledge of the particular sport you could potentially spot opportunities when the odds are misplaced by bookies giving you the mathematical advantage, but that's more about finding anomalies. By design, sports betting is not far away from "classic" casino games where the house has the edge. That's why we don't see many (or at all?) professional sports bettors.