The 5 star ratings are meaningless in basketball. In football it kind of works even though they are often wrong but in basketball you just go by how high they are rated in the top 50. Anyone in the top 50 should be capable of a NBA career even though they all won't end up being that. And yes there are some guys that are rated too high but Quickley and Richards aren't amoung them. Green however would have been about 100+ in my book.
You just illustrated a huge part of the problem. People wildly overestimate the number of players who have a huge impact as freshmen in college, and wildly overestimate the number who go on to do anything in the NBA.
Take the 2010 NBA draft class. Players from that class are in their 9th NBA season, with the guys who haven't missed major time to injury at over 600 games played. As of today, only 17 guys drafted that year have played at least 400 games in the NBA, and only 17 are still in the league. 32/60 never even reached 200 games played.
Of those 17, 4 were considered the top 4 recruits in the 2009 HS class (Favors, Wall, Cousins, and Avery Bradley) and 2 others in the top 10 are still in the league, with only 2 from the 11-50 range.
For the 2010 class, the numbers are slightly better, but still very low. 7 of the top 10 are still playing (including Knight and Kanter), 5 of the next 40.
That's 13 top 10 recruits from those 2 classes still playing, 7 guys rated 11-50.
And among the 9 top 10 guys who weren't from UK, you saw freshman college numbers like this:
Avery Bradley: 11.6 ppg on 43% shooting.
Derrick Favors: 12.4 ppg/8.4 rpg
Lance Stephenson: 12.3 ppg/5.4 rpg, 44%shooting.
John Henson: 5.7 ppg/4.4 rpg
Tristan Thompson: 13.1 ppg/7.8 rpg
Will Barton: 12.3 ppg/4.9 rpg, 42.8% shooting
Good other than Henson, who received limited PT, but not dominant.
The other 3 are Kyrie Irving, Harrison Barnes, and Tobias Harris, who were all really good as freshmen, though only Irving was really dominant.
Cal's first 3 recruiting classes at UK spoiled a lot of fans and skewed expectations of players towards the unrealistic.