Why do colleges put so much emphasis on SAT scores?

It is truly a shame that colleges nowadays focus so much on SAT scores as opposed to the genuine intelligence and dedication of their applicants. Many people are not efficient test takers but are genuinely intelligent and desire quality education, but are cast aside simply because their SAT scores are "average". Even above average scores such as 1630 (what I got on my PSATs) seldom get people into anything better than community colleges.