[jseliger]

I understand your premise and don't have any rebuttal to it that would include facts and/or figures. But one thought did pop into my mind when reading your comment.

See the books Academically Adrift, Beer and Circus, The Marketplace of Ideas, and, to a lesser extent, the post I wrote above. Grade inflation is sufficiently well documented that most academics now take it for granted, especially because they see it in action.