The SAT is a very imperfect measure but it turns out a lot of the others are even worse.
Putting a body every a seat for those profitable 500-person lectures taught by an adjunct and graded by TAs who are all paid peanuts and then having them wash out before those expensive 50-person high level classes and esoteric electives taught by tenured profs and accompanied by lots of expensive lab time is great for the university's bottom line though.
There are still some online courses that try to do this sort of thing, with a particular example being the University of Helsinky's Full Stack Open [0] which offers post-hoc university credits for those who complete the course, but it seems that the dream didn't quite materialize.