> Most Germans won't be able to pass a C2 test

That's not true, but it is a commonly shared myth. I've taken and passed C2 with the highest mark in every category (I moved here when I was a young teen, wanted to know if I would pass it after hearing years of people saying things like you're saying).

Most Germans would easily pass C2, although I think they'd have to be well-read/possibly university educated to get high scores (mostly need to be able to read quickly, give a semi-structured presentation and write a persuasive essay).

For what it's worth, I could run linguistic laps around all the other test takers there that day, and I assume at least some of them passed.

That's a really interesting experience. Lots of people in language learning communities have this argument back and forth for years. Have you ever written a longer piece about your education, preparation for the exam, abilities of other test takers?

For reference I scored ~C1 in German years ago (testdaf 4/4/5/4) and at that level there's no question at all about the vast gulf between me and an educated native speaker.