And why the best American oldies stations are European — I grew up liking Stairway to Heaven but I’m so tired of it now. I expect the Devil’s deejay plays nothing else. “You’re listening to Hell’s Oldies! Now, for the 783,864,913th consecutive time, here’s Led Zeppelin’s Stairway to Heaven!” Classic oldies radio stations have a library smaller than your great-great-grandfather’s…