I believe the European Court of Justice's ruling applies to all of the EU countries, not just to Spain. I think it's unimaginable that Google would stop serving the entire EU market on principle.

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.