And yet I still have no trouble believing that some American studio will decide to do a dumbed-down American remake of it. Just wait. It'll happen.
Or they could pull a Coupling, use the exact same dialog but set it in New York with American actors, so nothing they say fits the culture... What a disaster that was, turned off fans of the original, and I'm sure seemed "wrong" to people that never watched the original.
I agree Downton is really a high end soap opera, with great sets, actors, and dialog. It's not realistic or truly historical. I was just watching the extras on the Murder On The Orient Express DVD and they said when recreating a historical setting for fiction you try to get in as many details as possible in but as long as it "feels" right it's good enough, that certainly holds true for Downton Abbey.
For a show that was popular yet made you think, LOST comes to mind. But I suppose it didn't really
require a lot of thought, you could still enjoy it while being spoon fed bits of information each week.