MLB players earn the most money, but a lot of that is because they can play the longest. With a firmly established career length, an above average NBA player will do the best, especially if they time their free agency correctly. Working half as many days is a nice bonus. Since I'm white, being above average would give me very nice endorsements and post-career options
NFL union is way too weak and way too likely to leave the sport with health issues to come close; NHL just doesn't have the revenue to be worth anywhere near the others