Right now Tatum son is 6 and Tatum is 26, so Tatum would have to play at least 13 more seasons. It sounds crazy but the thought of Bronny playing with Lebron in 2010 (Lebron was 26, Bronny was 6) would have been a crazy idea back then. Out of all NBA stars, I think Tatum has the best chance to play with his son after Lebron
It only doesn’t matter if you’re the greatest basketball player of all time and still play like a current top 10 player at that age.
I don’t even know if current-level Tatum has enough gravity to pull a hypothetically unqualified son into the NBA.