There have always existed levels, some better functioning mechanisms than others.

I think it varies a lot from even year to year. For the same course, some teacher might be really optimistic and produces little explanations and tests with very hard problems, while next year there's a teacher who is very good at explaining issues and the tests are a bit less "gotcha" like. Even a single teaching assistant or a friend explaining some key concept in a way it clicks for the student can make a huge difference.

Or maybe you have different formal levels, ie university, technical school, so on, these vary by country and don't have full 1:1 mapping to each other. These also evolve over time.

Or inside one university, you have various levels. Some departments might be small and really hard to get to, either via exams, or proof of previous study ability like high grades. And there then you can expect more from the students.

So one big issue is to get the people sorted into the right places. Also if a person's performance or preference changes over time, they should be able to switch.