Good question. The SAT and ACT have been horribly dumbed down over the last decade, but you still have to be able to read and solve problems quickly to get a decent score. Kids that can't read well should not do well on the English and Science parts, and kids that need a calculator to find 2 + 2 should not do well on the math.
It has been brought to my attention that you can BUY a higher score on SAT or ACT tests.