OP, when I was marking final year law students I was paid about $60 per assessment. If my incentives are to assess 150 submissions in the shortest amount of time, how useful do you think those grades are?

How the fuck am i supposed to brag on strava if roads don't have grades?

Oh wait

There is no good way to grade students. Just let them all go to university if they want to go to university. Once they're in university, let them stay there as long as they want and let them take whatever classes they want.

Instead of evaluating students the way that we do now, teachers could just have a conversation with a student about the subject, or give them a test, and then tell them what stuff they should work on. There's no reason to have any punishment or reward attached to this stuff.