I'm not sure accumulated average grade metrics are actually very useful. Just the difficulty variation between courses means you can game those metrics with careful choice anyway, Or studying in ways that benefit the tests more than the subject.

Choosing difficult courses and passing is more valuable to the student. (well, a 4.0 on a paper is also valuable in a way, but more in a charade way)

What concerns me is not grade inflation, its difficulty and deapth deflation. I had plenty of courses that bored me but that had plenty of fun depth and difficulty that could have been covered with a bit more effort of students and teacher.

But we cannot measure courses difficulty and deapth, so we measure grade inflation instead. Which then lead us to false conclusions about how to solve it. (making the metrics more accurate at the cost of time and resources fir teaching the subjects)

i think less emphasis on grade and more emphasis on covered subjects could mabie shift the incentive. Its difficult to actually implement through because humans love maximising metrics... so it will remain my fantasy.