What you are talking about is still incapable of recommending (with a high chance of the recommendation being spot-on) new things. In music a new thing would be a completely different genre, not a new song in your favorite genre.
The system you are describing will find people who have a strong correlation with me and who also like:
1) Classical music and Justin Bieber.
2) Classical music and Metallica.
3) Classical music and Dubstep.
And it will recommend me Bieber, Metallica and Dubstep. I might like Dubstep, but I won't like Bieber and Metallica. How is it better than listening to random songs?
The system you are describing will find people who have a strong correlation with me and who also like:
1) Classical music and Justin Bieber.
2) Classical music and Metallica.
3) Classical music and Dubstep.
And it will recommend me Bieber, Metallica and Dubstep. I might like Dubstep, but I won't like Bieber and Metallica. How is it better than listening to random songs?