I'm curious what becomes the breaking point for them to pull out of a region. Obviously it's about profit but at what point (if any) does it make profitable sense for them to leave?
Presumably, before they take such a drastic measure, they would first spend massive amounts on lobbying, which would most likely succeed.
What would actually happen is that the US would start seriously threatening (blackmailing) the EU to a degree where it's forced to relent long before Apple would pull out.
Apple's estimated operating profit from the EU is around $40 billion dollars. If the US government wouldn't get involved, they could force Tim Apple himself to live on top of the Alps and he'd happily do it rather than lose that $40 billion, or shareholders would vote him out ASAP.
this would be a very losing battle for politicians
Politicians in fact pay lip-service to "data sovereignty", for the points it gets them.