The linked research does not provide evidence of the latter (i.e., that SAT score does not provide meaningful information about a student's ability to succeed i

The linked research does not provide evidence of the latter (i.e., that SAT score does not provide meaningful information about a student's ability to succeed in college), but it DOES provide evidence of the former (that the tests very much measure family income). It is quite possible, of course, and even quite likely, that higher income families will do better in college (since that likely means better education throughout childhood, as well as less likely to need a job or take on debt to attend, so less distraction, and in the event of struggle more ability to hire tutors and things), but the point is that to admit that "we're selecting for rich people" is to say the quiet part out loud; and colleges of course don't want to do that.