SAT scores is heavily correlated with income level (the data I have is for the standard tests, not the subject ones, but I would guess they follow a similar pattern).
Is it? I've heard about the movement to make the SAT optional for years. The argument was that grades correlate with success much more than SAT scores. That SAT scores were how privileged were "gaming the system" because they could afford tutors, can take it multiple times, and appeal for phony disability claims allowing extra test taking time.
I'm all for objective tests, but a single test mostly shows subject knowledge, not necessarily success. When I studied and took them, I always felt like it mostly evaluated standardized test-taking skills (which is a trained skill I feel many smart and successful people lack). It doesn't show anything if people cheat or if the process is gamed.
I don't really have a strong opinion either way--this is just what I've gleaned from following the news over the past few years. Here's an article I found that mirrors what I've heard: