In addition unless Microsoft wins its appeal US courts have ruled that a US company eg: Dropbox can be forced to provide any data they have even if it is outside the US
(When she joined Dropbox, there was a huge fooforaw over whether her actions under Bush during the Iraq War constituted war crimes. Honestly I felt like that was a red herring in this particular case--regardless of your feelings the war, it should be obvious that you don't want even partial control of your private documents going to a person who thinks that the government should be allowed to read your private documents.)
I'd suggest "ideology" is a much more powerful motivator here.
That's a bit of an overstatement. I think what you mean is every huge tech company or something along those lines. And I doubt it is even true for every member of that cohort. Though you are of course correct that it is common.
There are plenty of companies registered in Ireland which do not have a physical presence here. There is no test of what proportion of business activity occurs in Ireland.
For example Norwegian Airlines has something like a dozen " brass plaque" companies registered to a solicitor's address in Dublin but the only time their 787s touch Irish soil is on their delivery flight, to receive their EI- registration