Brad - I think my comments have run dry, but I do have to point out you keep naysaying and pointing at the problem with China, with India, with Bavarians distrusting Prussians, etc, and yet every one of those examples concerns a country that is still a union.
Sorry, but the convincing cases for me are going to be places like Ireland and the Soviet Union where there actual was a breakup, and then looking at the EU and seeing if the factors that caused actual breakups that have actually happened apply to the EU.
I think the elites are way to far ahead of the people on European unification.
Now that I think is a problem with the EU. Switzerland was the country where the elites failed to convince the people altogether. In the other countries, the votes passed, but it is questionable there was ever much buy in.
That is a difference between all the successful cases I mention - in those case the regular people mostly didn't care all that much.
Don't get me wrong - making the EU last for its first 100 years will be a major challenge (and I would only start counting from the Schengen Agreement of 1995). I think it's highly unlikely that it will survive, but not because of any single factor.
I think it will be torn apart for the same reason that most things are torn apart: because there are a million factors that are all one in a million, and so eventually one of them comes to pass. Nothing lasts forever, the question is how long will it last.