Revlon's announcement last week that it was exiting China is just the latest proof that this once-dynamic market is either going through some growing pains or showing the first signs of old age. Revlon's announcement comes after Avon Products reported that its revenue plunged 67% in China in the third quarter; that's a significant acceleration from the first six months of the year, when revenue fell just 28%. Similarly, Procter & Gamble said it's losing market share in...