[LaMarseillaise]

It was implicit in your statement:

> Without pressure from grades, [students] won't do the work of learning.

If it were qualified with ‘many’ students, there would be no such confusion. Your comment, as-is, is trivially falsified by the example of any auto-didact.

[WalterBright]

That's not how the English language works. The reason the adjective "all" exists is strong evidence that when one says students (plural) one is not saying "all" students.

If one meant "all" students, one would say "all students", "students without exception", "100% of students", "every student", etc.