[stdgy]

Could they house their data in a separate company that was founded in Ireland and is not an Alphabet subsidiary to get around this?

[lucideer]

IANAL but I don't believe this commenter is correct. If they were, this would essentially prohibit any non-EU company from doing any online business with anyone within the EU.

I suspect the issue is rather that Google Ireland are not in fact exclusively housing EU data within Ireland (or the EU in general).