Mark Cuban has a very specific standard for who is and who is not a superstar. As he told Mavs Moneyball's Tim Cato:
"The way I define a superstar is who do you want the ball in the hands of at the end of a game when you need a bucket. Who do you know that can get off that shot, make that shot and that's your superstar."
As far as his thoughts on Draymond Green, specifically:
"I think Draymond's an All-Star and I think he's really, really, really, really good, I think he's multi-faceted, but I wouldn't call him a superstar yet. You're not going to put Draymond on a bad team and watch him win 50 games. Draymond, he makes all the players around him better, but I don't think he goes anywhere in the league and wins 50 games."
For what it's worth, he doesn't think Kyrie Irving or Russell Westbrook are superstars either.
Slightly related:
What do you think Dubs fans?