Actually the best predictors of college success are high school grades and AP test scores. The SAT is a lousy predictor of success in anything. I should know, I aced the SAT!
Don’t worry—a certain percentage of high SAT scores are simply outliers where the results don’t show the test-taker’s true ability. That’s why repeat high scores are more significant than one-time scores. ;-)
And the data show SATs are about as good at predicting college success as are grades alone. AP scores are good too, but less broadly applicable because fewer students take AP classes and tests.
AP test scores are definitely a good indicator, although they are focused on detailed knowledge of one subject rather than general verbal and math ability.
I got a 1598 on the SAT back in the days before they began revising the thing. My daughter got a perfect 2400 (after 3 tries and some tutoring to bring up her 780 math score). We definitely employed a "playing the system" approach, but the whole goal of our high school was to get everybody into the college of their choice. And to equip you to manage when you got there. Absolutely a "prep school" for the college bound, not a general high school.
I would like to see a "two-track" system restored, or a "three track" system: a college prep track, a general business/tech school track, and a babysitting service for kids who do not care to learn and disrupt those who do. But that will NEVER happen - too many people cringe at the idea of admitting that some kids are better equipped to learn than others (whether from native intelligence, hard work, or determination).
It predicted that you are highly adept at test-taking. Nothing more, nothing less. As for success on campus or in the business world, that is entirely different, and the tests are much more subtle.