If betting is a skill, it would have make many gamblers a millionaire today, and many gamblers would have like to be using any amount of money to gamble because they know they are going to win anytime they play. If you are skillful on a particular thing, you will not be afraid of losing because you have the skill to know the final result before the end of the betting.
Someone who have skill doesn't mean they will never make mistake, let's say in Mbappe in football, even though we know he's currently the best player, it doesn't mean if he play, he will at least score a goal.
We know Mbappe has a very good skill, far above than average football players, but there's always a luck will play. Like, the ball hit crossbar, woodwork, his teammates sucks, or the opponent goalkeeper is as good as him.