But what happens when senior data scientists at Google want to do some analysis? Each dataset for each global region can't remain fractured from each other. The subsidiary may not have to hand it over to the US government but does the GDPR prevent data from leaving the EU zone? If not, then local copies in the US would be exposed.
I think there would be a lot of loopholes that needed to be closed. "Will be" a lot might be the better choice if words if France's decision becomes guiding legal doctrine in the region.
I don't think Google would willing give up that data either so they could be forced to change their practices to at least get that which allowable under EU law. And I don't want to get too slippery slope in this, but that could mean privacy-minded services begin using servers in the EU as an added layer of user privacy.