The muted GOP reaction to Sarah Palin’s departure from the Republican presidential field Wednesday suggests the party had moved on months ago. Not so for the thriving cottage industry that grew at her feet, and whose future is now in danger. Palin-lovers, Palin-haters, a half-dozen publishing houses, and elements of the mainstream media who tracked her plans long after the Republican campaign bypassed her suddenly face a future without their entertaining, unpredictable, and now scarcely-relevant subject. Palin’s circle of online admirers greeted her announcement with shock and dismay. The camp who saw her as a nascent American Mussolini, with shock...