When Google was banned in China for directing them to a mainland site in Hong Kong that was unfiltered, they only came back four months later, agreeing to all of China's demands. Google had promised to abide by the Chinese government, as well as "avoid linking to material deemed a threat to national security or social stability."
As I suspected, Google doesn't make nearly as much money in China as it does in other countries. The Chinese market accounts for "an estimated $US250 million to $US600 million of Google's projected $US28 billion in revenue this year." However, it is feasible that without "the China platform," Google would not be able "to profit from the expected future growth of the market."