you can count the records sold by the AI artists on two hands.
Hmm. Kelly Clarkson, Carrie Underwood and Chris Daughtry have sold more than 32 million records. I agree that Idol is much more miss than hit, but when it hits it hits big.
I've always thought Idol's big problem as a vehicle for creating pop stars is the show's soul-crushing reliance on song genres that are far afield from modern pop music. I suppose disco and Motown classics make for good television, but they don't make for successful music careers.
Also, the European music market has always been fundamentally different sales-wise (and taste-wise). The charts "burn" about 3x faster than in the States, especially singles. So it's hard to compare them directly. Still, your basic argument that most Idol finalists don't wind up with successful music careers is correct.