[roel_v]

"I have heard from someone that there is a specific instance where students do not partake in an education that is optimal for every single of them" != "The education system, in at least some locations and some subjects, is indeed declining"

Just describing the current state of affairs is by definition insufficient to be able to say something about the evolution over time of the quality of said affairs.

[nitrogen]

Not over the past 100+ years, no, but between two years ago and two years from now, yes. Further, this isn't a change that is not "optimal for every single [one] of them," this is a change that is significantly suboptimal for the majority of students.

[roel_v]

May be, we don't know; if you have data or (somewhat) robust theories on why and how, please tell. My point was that your 'proof' wasn't proof at all for your stated premise. I suspect this will be hard for you, because I don't have rational reasons to believe that such a sudden drop-off is happening. I don't really know though, I'm just trusting on an abstract 'common sense' approach; the best I have in situation like this where objective measure are not available (to me).

Anyway please feel free to share your theories and data on why you think that over such a very short amount of time the level of education will take a sharp drop-off.