Mark Cuban’s basketball team isn’t where he wants it to be just now, but the Dallas Mavericks owner couldn’t be much happier with the position of his league these days. Cuban, who envies the Celtics’ quick rebuild, avoided any urge to gloat about the NBA’s rise in TV ratings and popularity while the NFL slides. He was, after all, most prescient 3 1⁄2 years ago in his prediction of the football downturn because of overexposure. (“Pigs get fat, hogs get slaughtered.”) But the man who moonlights as co-star of TV’s “Shark Tank” also noted the participation issue raised by greater knowledge of head trauma, as well as playing to a key audience. “There’s a confluence of a couple of things,” Cuban said. “No. 1, our demographic keeps on getting younger. The NFL and baseball, they keep on getting older. And I think what we’re doing with (the video game) NBA 2K is brilliant. And in the bigger scheme of things in terms of building fans for the future, what do you want your kids to play? I mean, of all the sports out there, do you want to go to a baseball game, or do want to watch your kid play basketball? Do you want to worry about him a whole football game, or do you want to watch your kid play basketball? Do you want him to get healthy from running the court, or do you want to watch him play football and worry about collisions. “I think we all have structural issues in terms of kids not watching sports like we did, because television isn’t primary anymore. And I think what really makes the NBA stand out heads and tails above every other sport is you know our players. Tom Brady, (Rob) Gronkowski — how many other football players, if you saw them from the Patriots, would you know? Maybe (Julian) Edelman?” Someone mentioned Brandin Cooks.