I think that the real key is that they sacrificed long-term success for the quick buck. Sure they are selling tons of albums and concert tickets now. But they were before too. Before they sold out, I read that they were already the best-selling heavy metal artist of all time. As soon as they lose MTV and radio airplay(and they will, everybody eventually does), all of these fair-weather fans will jump off of the Metallica bandwagon. Then what are they left with?