Joanna: That crossed my mind too, but I observed a similar divide elsewhere. When I was still teaching, I saw a big difference between college kids and older folk coming back to school to supplement their education. I am not talking about knowing more facts, for both groups were more equal in their priors re. the subject matter, but their communicative skills and their skill of learning new things. One way to describe it is "attitude" but I am afraid it may create wrong connotation. I am not talking about "behavior problems" but about general interest in learning new things - which seems to be vanishing.
Similar observations were made by other teachers and, incidentally, by my own kid when he was still a student. So I think the trend is there, Yoshie's flippancy notwithstanding.
Regarding your argument concerning speakers of English as a foreign language - I concede you are right.
Wojtek