Personally, I think the idea of a Retromancer is absolutely hilarious, given some of these rock bands seem to just keep on going, decade after decade, despite how much substance abuse and shit that they indulge in. It's almost like the fan's love for them is literally keeping these old rockers alive, and I think Gillen and McKelvie quite subtly tapped into this, in a way, by suggesting the musicians are aware of this and leech off their crowds deliberately.
It's like saying Lemmy keeps going just because he keeps on playing Ace of Spades to crowds of thousands every year.