The real risk of Google entering China, and possibly succeeding, is the a reverse-effect happening with regard to censorship globally. The theory is, by Google operating in China, it will help liberalize and open things up, that may have worked in the Deng Xiaoping era when, but after the hardliners took power, and especially with Xi, things are going in the opposite direction of the "End of History" folks predictions. Economic well being did not bring an appetite for Democracy, it brought an appetite for not "rocking the boat"/"don't mess with a good thing"

By reverse-effect, I mean, let's say Google is hugely successful in China. It proves a censored search engine works and is good business, first of all. So economic arguments about the harm will be delegitimatized. Other states will ask for more censorship, and Google can't reply 'this is too costly or harmful to our business' because China would be an example of how to make it work. So the end result might be that Saudi Arabia, and Turkey, and Indonesia, Brazil, Zimbabwe, etc will all of a sudden be asking for their own forks of Dragonfly. (I just picked those countries at random, with no specific example of censorship in mind)

Secondly, if they become hugely successful in China, it compromises them just like Apple. The revenue stream will become a golden goose and too valuable to risk the anger of the government. So you'll have Google executives having to embarrass themselves like Tim Cook by praising China's "open" internet (https://www.washingtonpost.com/news/worldviews/wp/2017/12/04...)

Third, Google made one of the few brave moral decisions leaving China. Perhaps you don't believe Brin did it for the reasons claimed, but your belief isn't important, what is important is what many people believe this, especially politically repressed people who need to believe in heroic actions. This undercuts that decision. If the world's most popular company for organizing information not only fails to fight censorship, but actively helps regimes that wants to implement state level censorship, it will be a big loss of a beacon in the constant struggle between censorship and anti-censorship forces. Having the world's largest companies, even if they're only doing it for economic reasons, on the side of anti-censorship is better than having the world's largest companies on the side of censorship (for economic reasons)

And fourth, Google can't change China. The idea that a SV tech company can trigger improvements in the politics and openness of a powerful country like China is quite simply hubris. We're not smart enough to do this, and intelligence isn't even the factor. China's future will be written by its people and internal events.

If they want an uncensored search engine, then one day, the political winds will change, and they will demand it. But until they do so powerfully enough for the current government to change its behavior, the actions of foreign firms won't do anything. I'm not sure we should involve ourselves in this fight other than through NGOs that already fight these things (e.g. Amnesty International) or offering anti-firewall/anti-censorship tools.

There's only one argument for doing business in China as a search engine, and it is a legitimate one, just not a moral one: the shareholder argument.