1) Popularized by NBA superstar
Kawhi Leonard, the board man, who is the person doing all the hard work of rebound that is usually not in the spotlight of the basketball game. The saying in this context simply means anyone who is working hard should get a matching reward for their hard work.
2) This saying can also be traced back to
Afro-Caribbean communities where during the table games such as pool or ping pong, the board man is the third person who
ensures the game is fair. In this context the saying means that whoever contributes to the success of anyone or anything, should be rewarded as well for their continuations.
Emergency workers deserve to be
recognized and rewarded by our society just as entertainers. I mean,
the board man gets paid, yeah?