I didn't see it mentioned but don't EK/EY/QR take advantage of US EXIM bank financing, something that US (and EU) airlines are forbidden to do?
All of the US carriers are getting export financing on the regional jets from Brazil and Canada, nothing stopping them from getting export financing for Airbus aircraft or RR engines.
US carriers cannot get EX-IM finance, as being a domestic airline, it is not being exported.