It is not such a big problem as you would imagine. The money comes from businesses, not consumers. As far as I know, the US and EU markets have the highest value consumers, so even Google is outside China, it is making a lot money from Chinese advertisers. The biggest problem for Google is competition from other advertising platforms, I don't remember last time I searched for a product on Google to be honest.

I believe the core ad platform for Google is going to be YouTube, it is the only one I am not leaving now.