If someone becomes successful in sports betting over the long run, would you say that’s because of luck or skill?

There’s been a debate in the forum, some believe that gambling success is purely luck, that no real skill is involved, and that it’s not something to take seriously because eventually, you’ll lose. But there are bettors who have consistently made profit and proven they can win in the long run, believe it or not.

So the question is, can we still call that luck? Or is that already skill at work?