The thing is, Google wasn't really making money in China. They failed to take much search market share from the incumbents (particularly Baidu) and their China operations were costly.
This has led many, myself included, to think that the whole free speech and hacking angle that Google is now adopting is just a smokescreen. It lets them save face and leave a market they've failed in while getting kudos from the internet community for standing up to censorship.
The primary evidence for this idea is that China has the same censorship and government hacking policies today as it did years ago when Google entered the China market, so why leave now? Because they've failed to meet market share and profit targets.