Surprised that Raf Simons is leaving Dior? Don't be. Fashion is a rat race like any job.

The announcement that designer Raf Simons is leaving his post as creative director of Christian Dior was dispatched without warning, without the usual swirl of rumors that typically precede the departure of a star designer from a major label -- in this case, France's most venerated house. There was no tortured speculation about Simons's degree of contentment in his role. No fretting about how the clothes were playing among consumers. In fact, revenue at the house was up.