Who is Adam Silver and from where does he derive his power?

Who is the mystery man behind the NBA, the one with the bald head and the big ears? Sterling is clearly an idiot and probably senile, so this is no defense of him. Back to Silver. Since the NBA is a non profit, why was the commissioner job not opened up to any applicant? Why is the Silver the successor of Sterne? Is this a monarchy with tax exempt status? Why are former players not allowed to apply?  How about Condi Rice, who is interested in baseball? How about people from academia?