>What if raw SAT score doesn't perfectly reflect lifelong achievement?
It was never intended to?
>How does one account for that?
It's impossible to account for everything. As much as the thinkers of the Enlightenment and their successors have attempted to quantify and measure everything, it's simply not possible in reality. If someone could devise a better means of measurement than current standardized tests like the SAT and ACT, I would happily welcome them.
But one thing is pretty clear and certain: the SAT is a far better measure of mathematical aptitude that high school grades, and until better measures can be found and implemented I fully support continuing to use it for college admissions and college math placement.