Why American Idol Keeps Soaring

Theoretically, American Idol should not exist. It's a broad-based mainstream hit when series like that are no longer supposed to be. It has gained viewers in its sixth season, a TV near impossibility. It sells albums, at a time when very little else does. And by awarding a record contract by nationwide vote, it is dedicated to a heretical idea in the niche-media age: that you can please most of the people most of the time.

But weirdest of all — and I'm betraying my professional...