"Jackson is the best prospect in this draft. So it's no surprise he's so good."
Saying he's one of, if not the best, PROSPECT in the draft doesn't mean that he'll be a star in the NBA. Of course that is the hope but that's never a sure thing and there is a difference in calling someone a top prospect and a future star.
Look back at the 2013 draft, it was said Len was one of the top prospects that draft but he's not a star and never will be. No one taken in the lottery from that draft could be called a star but those were the players considered top prospects that year.