Under some interpretations of the laws, Google would need to ensure that nobody under US jurisdiction has any access to the data. A full "split" would be difficult, and seemingly break a lot of the large-scale load-balancing and redundancy of Google. And what happens when a new, separate, jurisdiction arises?

While it would be technically possible, I think Google are probably happier just not dealing with the more paranoid businesses that are worried about this. That's the impression I got when discussing similar issues with their sales staff.