No internal customs, easy trade and travel between the multiple relatively small countries, and a very stable common monetary unit, are "nothing to show for"??

If you had lived in an EU country that wasn't in the EU 20-30 years ago, you would've known damn well what's there today to show for. You either don't live in the EU or you've got amnesia and can't remember what it used to be like. Cut your bullshit.