Difference is the EU actually is falling apart right before our very eyes whereas the US shows absolutely no indication of splitting up in the near future.
Keep denying it all you want, but that doesn't change the fact that it is happening. And like I said, it may not dissolve completely, but it's not going to to survive in its current form. Turns out Europeans aren't too keen on having their unique national identities eroded away and replaced with some fanciful notion of a "unified European culture". I see the EU going back to just being an economic arrangement similar to the old EEC.
EDIT: I must know though: You are clearly a staunch defender of the EU, but...why? It's not even a nation. It's a supranational body similar to the UN (if the UN's resolutions were actually binding), so I find anyone expressing anything resembling nationalism towards the EU to be as odd as someone expressing the same sentiments towards the UN.
Also, you seem to think it would be some great tragedy if the EU disappeared from the Earth. Again I ask: Why? Europe got along just fine before the EU, and I'm sure you all can survive without it.