i believe, there are few of these sportsbettors who can win in the long-term. but those sportsbettors somehow invested some of their winnings to businesses, so even if they go back to betting, they have other means to earn money, so they are not totally broke.
Have you actually met or heard about any real-life long-term profitable sports-bettors, or do you just believe they exist?
If the story is real, the very fact they they had chosen to take their capital and invest it somewhere else would indicate that they themselves didn't have much faith in their betting skills working long-term.