One reason I believe that SAT scores have declined has been the requirement that all seniors take the exam before they are awarded their high school diploma. I know Maine had that requirement for some years. So students who have no intention of going on to college were required to take the exam and really did not care how they did-so minimal if not zero preparation and probably just filling in the ovals for some parts of the test.
Your scores are recorded by the government. If you are interestingly smart they find you. And if you are interesting for other reasons, they look at your scores to get a better picture of you. Also, colleges like to drum up business. Unfortunately college is not very useful any more.
Of course it was fun to go watch your high school basketball team getting blown out, just so you could chant “SAT SCORES!......SAT SCORES!.....”
The SAT saved my bacon for college acceptance because my grades weren’t great (laziness).
The SAT was dumbed down several times in the past 50 years. They cannot deny it was because they bragged about it. Said it was “inclusionary”; meaning, DEI.