I think if you were to wake either of them up they would sound just like you or me, but after the first cup of mocha they recover those plummy accents.
And see Henry Kissinger: he’s lived here a half-century but still sounds like a kraut right off the boat.
I’ve met plenty of Swedes and Germans, Vietnamese and Cambodians and Malaysians who speak English like they came from Iowa. No accent, or only a very slight one.
Agent Olivia Dunham on Fox’s “Fringe” is an Australian actress who has mastered “American English” for her role.
So why can’t Hitch, Kissinger, and Amanpour do it?
Answer: They can but it’s not fashionable.