The Dallas Mavericks drafted Luka Doncic in 2018. He was 19 years old with all the potential in the world. Doncic had just won EuroLeague and Liga ACB MVP with Real Madrid. He was by far the most accomplished player in his draft class. Fans may never know why the first two teams passed on him, but the Mavs jumped at the chance to trade up for the rights to Doncic.
Nobody expected him to be a superstar before turning 21, though. Luka became great in his second NBA season. He is a triple-double machine.