The news coverage following Google's announcement that it may be forced to leave the Chinese market has focused heavily on the declaration by Google that they will no longer censor search results for users in China. This is a convenient point of focus, and makes for easier story writing, but it doesn't cover the scope of the issues Google currently faces in China.
Or, briefly, there is a strong business case to disengage from the Chinese market if attacks on Google-hosted information are going to continue, possibly powered by the PRC government itself. Google is currently in the process of expanding its business beyond majority advertising (currently about 97% of its income) to enterprise and cloud computing style solutions. If a significant national entity is accessing Google's IP and the hosted content of Google users, this may damage the trust of current and future Google customers in the company's ability to provide safe, reliable, and most of all secure tools for their business and other needs.
Moving away from the ceding of censorship rights to the PRC is good, but Google's potential decision to leave the market altogether will necessarily be a consequence of their desire to ensure that they can provide secure services for customers in the rest of the world. Although a 30% market share in search in the PRC is impressive, that may well be worth trading off for the ability to expand their business in the rest of the world.