Interesting. I have to admit, I had never quite thought of it in that respect. Obviously, we all know that downloaded music is sonically inferior (usually) to other sources like cd's and lp's, but I never considered that it's not appreciated because it's so easily available.
When I was a teenager I would buy maybe 2-3 albums a month. So there was a commitment (financial and time) to the album. Even if I didn't like it I would play it quite a bit thinking it would grow on me (they usually did, too) - Hey, I had already spent my hard-earned paper route money - I was going to give it a fair shake.
With the ease of downloading (and free music, I assume) it seems it would be easy to not appreciate the things that don't immediately grab your attention - I'm thinking of younger people, but I suppose it applies to anyone with lots of music access.