Most of us here on HN are entrepreneurs. We wanna make something useful to the world and make tons of money in return. Just as we should look at what kind of impact our products have on our users' lives, in the discussion of whether Google should return to China, we shouldn't focus on the Chinese government and ignore the 1 billion Chinese people.
If Google launch a new Google.cn:
1. The Chinese government won't benefit much from this. Compared to these Chinese companies, Google will always be an outsider. It will have to work with the government, but won't be eager to do so, and might cause troubles to the government from time to time.
2. The Chinese people will benefit a lot! Without good competition, the dominant search engine Baidui has become such a bad actor over the years. If you are annoyed by Google ads, Baidu is 100 times worse, especially on mobile devices. For many search terms, the first a few pages are all ads. People are really fed up with this. In a recent survey by Sina (http://finance.sina.com.cn/stock/s/2018-08-07/doc-ihhkuskt26...) 72.8% the users surveied wanna use Google if it goes back to China.
If you were a farmer in the North right before the civil war, you probably would still have been willing to sell to the people living in the south that are against slavery, even if Southern government would benefit from tax.