“Wicked” is in Chicago for an extended stay. It’s earning more than $1.1 million a week at the box office. “Ponder for a moment the astonishing appeal of “Wicked.” Many people think “The Producers” was a hit. Yet its tours have dribbled into decline. Overly dependent on its original stars and with a limited urban audience, “The Producers” was a solid performer, for sure, but its New York staying power actually is turning out to be nowhere near what many people predicted. “Wicked,” which got lousy reviews compared to “The Producers,” is a genuine popular hit. And those come around about as often as a tornado hits Oz.”