But let's take UIUC's engineering class. When I attended, it was almost entirely in-state and almost all white. Now the percentage of out-of-state and foreign is far, far higher. The demographics changed considerably.

The SAT people have said that the tests have been re-normed because they are not absolute metrics. They are meant to reflect relative performance. So you can get more people at the high end when the test is easier for average takers.