It may be more cost effective for Google to stop serving search results in Spain.
Before you call me ridiculous, how much do you think Google makes off of those 47 million Spaniards each year, and how much do you think it will cost Google if those 47 million Spaniards or a large portion of them start demanding the company remove information about them?
If the cost to comply is greater than the profit, what would you do?
But you raise a neat question: assuming it was just Spain (or the next similarly sized country to reach this decision), what would happen if Google threatened to entirely pull out of the country--i.e., stop serving search results or supporting any Google services there? Are they powerful enough to influence national policy? It seems unlikely, but it's a neat hypothetical.
China is a hell of a lot bigger than the EU.
And tbh, you won't see many lawsuits where people try to enforce their "right to be forgotten". We may have stronger libel laws here but we don't have the lawsuit culture of the US. There's no way it'll be cost-effective for Google to pull out from Spain or the EU.