You would not need that intervening corporation in Ireland for income tax reasons but there are probably good business reasons for putting a layer between you and the US company.
If you are a US citizen you are taxed on your wages no matter where you are on Planet Earth. Some relief is possible (first approx $100k not taxable, for instance).
If you live in a country with no income tax then your US income tax is a net cost to you -- making you poorer compared to that British coworker who makes the same salary as you but pays no UK tax. Look around Dubai. Count Americans and count British people. Tax is part of the reason.
Thanks for this, by the way, very informative.
Correct me if I'm wrong, but after that $100K deduction you're essentially paying the higher of the local tax, or the US tax?
expats pay tax on full amount to host country, plus tax on amount over $92k to US. So the money over $92K is double taxed - making it "pointless" (not completely, obviously) to earn that extra
Example: So your US corporation "pays" your Ireland corporation, who than pays you in the EU? Would that avoid the income from being considered US sourced?