Ofcourse there are plenty of exceptions and being a 5* recruit doesn't guarantee success at college or a trip to the NFL. Surely, there are 2* players who developed in college and made amazing NFL players.
That being said, high school rankings mean a lot. What teams over the last 5 years have pulled in the most 5 and 4 star recruits? Its no coincidence that its the same schools who have been finishing in the top of the BCS every year...Florida, USC, tOSU, Texas, LSU,. Also, its not like the guys I listed suck. Turner is in the NFL. 2 or 3 members of that o-line will end up in the NFL. McKnight will get drafted next year. USC is loaded and theres no logical argument to deny that.