My guess is that you don't often download new tunes that are hits. I notice that it's the new tunes that have current airplay that have the most issues. I think the labels are putting out the junk files to discourage downloading. I can't verify this, but it makes sense to me.
Funny thing is, these labels are trying to sue the little guys for downloading, but they are often doing nasty stuff themselves. For instance, Sony (one of the big labels) recently got busted for Payola. That is, they were paying off the radio stations to play their music. Ever wonder why flipping around the stations on FM doesn't net you very much difference? Sony doesn't wonder.