By correlation, I mean the top teams in recruiting rankings, generally speaking, are the top teams in the final polls, the best teams in the nation. Of course it's difficult to ferret out who's #1 vs. who's #4, or #4 and #8, but the general drift is strong. Top ten teams get the best players. They aren't highly ranked just because top ten teams want them, the top ten teams want them because they are the best. And exceptions abound, but in general the correlation holds strong. If the top ranked players were only ranked because the top teams wanted them, the top teams wouldn't be top teams. C'mon, just look at the top ten at the end of the season. Almost all have high recruiting rankings over the last four years. As I said there's some bias, but not as much as some would like to believe. The proof is in the results.
If Notre Dame wants a recruit, he suddenly changes from a 2 star to a 3 star. If Nick Saban wants a player, his star number will increase. There is indeed a direct correlation between who is recruiting a player and what his rating is. The explanation for C'Bo last year was that the interest from ND caused them to "re-look" at him and they noticed that they had mistakenly ranked him lower. If that is indeed what happened, then what would happen if they "re-looked" at every two-star?
Alabama is probably going to do well and end up in the top 10. If you rank their valued recruits highly, then your rankings will probably look good. The mutts are probably going to do well and end up in the top 10. If you rank their valued recruits highly, then your rankings will probably look good. LSU is probably going to do well and end up in the top 10. If you rank their valued recruits highly, then your rankings will probably look good. Ohio State, USC, Penn State, Clemson, Oklahoma, and Notre Dame are all probably going to have good seasons and are likely to be in the top 10. If I ran a recruiting analysis service and ranked their valued recruits high, at the end of the season my top recruiting rankings teams would probably closely match the top 10.
Look at the other side. Over the last few years, USC, Miami, Oregon, and Florida State have recruited very well according to the services. Are they in the top 10?
My point is that if you pick the factory schools and rank their recruits high, then you will get the same result that you are saying is "proof" that the rankings are correct. Those teams in the top 10-15 recruiting rankings have probably recruited better talent. However, the recruiting rankings aren't a verification of that, they are simply leeching off of the factory schools to make money.