Yep, agreed. It's a numbers game to me too. If 1% of the chinese population have the means and inclination to buy products online, that's still 12mm people... now let's talk crazy and say 5% of the population do that a few years down the road -- that's 60mm.
Keep in mind that GDP is growing at around 9% (apres economic 'cooling measures') -- after about 7 years, per capita income will have doubled.
I've tried to find data on top income brackets in china, but so far no luck.