SAT scores correlate highly with academic performance. This should come as no surprise, since their whole purpose was to democratize college admissions by allowing those students who would do best at college to be accepted, regardless of their religion or social connections.
The fact that SAT scores correlate poorly with workplace success is a red herring -- SAT scores were never supposed to predict workplace success.
SAT scores are actually pretty decently correlated with freshman year grades. Colleges wouldn't use it if it weren't predictive, and so the College Board has put a lot of work into ensuring the test means something. Then again, freshman year grades don't really mean much in the grand scheme of life, but they do mean something, definitely.
The fact that SAT scores correlate poorly with workplace success is a red herring -- SAT scores were never supposed to predict workplace success.