And within a single generation one member of the EU already has left it. It's not a stupid argument when the US has a proven stable political history of 250 years outwith one singular dark period of Civil War. A similar relationship may develop in Europe. However, it's not stupid to point out that may does not equate with will.
I personally think a pan European identity is forming. However, I just don't think it is linked to the EU. I believe the newly forming European identity will destroy the EU as we know it. We see it in the rising populist parties in the likes of France and Germany.