But that still doesn't account for classes where everyone gets an A or a B. I know of teachers (not in my school) who have been pressured by the administration to change grades, or have had the grades changed for them. I've heard of classes where the median grade is in the 90's. So everyone does incredibly well, and colleges have no way of determining who the better student is.
I think that the SATs &/or SAT II's are going to be the method of choice of determining college acceptance for the forseeable future. So I think that kids find a lot of value in doing well on them.
Ideally, that would be accomplished by paying attention in class, by reading everything they could get their hands on (and not just in the months preceding the exam) and so on. But a lot of kids do that, and still struggle on the test. For those kids-- kids who are good students but find the SATs difficult-- I think the prep classes are just what the doctor ordered.
For kids who are going because their parents are making them, the courses are much less useful. I have called parents to let them know that their kids were wasting their SAT course money.
Oops, gotta go