That's part of the problem with these rankings. Some of it is how good a player was in HS, but a lot of it is projecting them forward how they wiil look a year or two or three after college. That's why sometimes you'll see a player like Reed Sheppard come in and people will be like, who knew he could play like that. He's a really good basketball player now, but what he does might not seemed to have projected well to the NBA.
Just watch other freshmen around the country when you can. They are actually better players than the 5 stars ranked ahead of them, but they might not be prototypical looking players so they are ranked lower despite being better at the actual game currently.