Why would you delete everything that’s less than really good? Some of us still like albums… to experience the complete ups and downs of an artist, even different moods that aren’t particularly our own cup of tea, but when experienced with the full range of a particular artist forms that particular artist’s cup of tea… some of us listen to rap/hip hop that may have spoken word sketches, intros, or skits, that you don’t want to rank as music but you don’t want to delete… etc…

Essentially I agree that it’s wrong to assume a bell curve distribution of stars. In my couple of years of using iTunes I know that I am much more likely to rate a track 4 or 5 stars if I really like it and everything else is unrated.