Portland Trail Blazers guard CJ McCollum has been interested in the business machinations of the N.B.A. since early in his career. He was a team representative and vice president in the players’ union, the National Basketball Players Association, before he was elected to succeed Chris Paul as its president this year. The job pays nothing. It adds phone calls and video conferences to his already busy schedule with his day job. His wife is due to deliver their first child any day now. He has a fledgling wine business. Why would McCollum want to take this on?