Musical enough that people agree it "must be" good.
Insipid enough you can play it at parties.
Helps make you look open-minded.
Has members of downtrodden groups, including homosexuals and minorities.
Basically, it's like a coffee table book that says "I'm profound, I'm deep, I'm witty, I'm compassionate and I have no rough edges that prevent you from molding me into your life."
The last band to do this was the Dave Matthews Band, who had songs that were all chorus and went nowhere, but people gabbed bug-eyedly about how good he was as a guitarist. More chicks gave up the poon to DMB songs than those of any other act. For guys, it was like having Enya or Tori Amos around: put it on in mixed company for socially lubricating results.
Now Opeth is the new Dave Matthews Band... a masterpiece of image, and no value as art.