Since pop music went from fun and infectious to annoying and whiny, have young people been able to get more done? Yep -- high school sophomores did a lot more homework in 2002 than in 1980.
I recall easily distracting myself with music while trying to force myself to study. But now it'd be impossible, except for the tiny minority of young people who have more INXS than Linkin Park in their ipod. Really, what else is going to tempt them away from their textbooks -- all that engrossing reality TV?