I suspect you have gotten it wrong with the nations you have listed. Currently they are among a group of EU nations being kept afloat by EU subsidies. They are hardly likely to jump ship and go it on their own. And the refugee issue is all about proximity and not about the EU itself. If Canada and the US were less than 200 kilometers from Africa we'd be flooded with refugees too.
Also, currently the EU features seven of the world's top 20 banks and if you google Eu bank failures you will find that all of the banks in Europe that are struggling seem to be in Italy. As for its economy the EU economy grew at a rate of two percent in 2016 which is about the same as that of the US.
You may be right. Perhaps the EU is doomed, but I doubt that the thousands of complex agreements that tie it together will disappear any time soon.
I think you'll find that those nations that are listed that are being kept alive by EU subsidies - subsidies which are unpopular amongst many EU citizens because it's their money which comprises the subsidies - are only in the state that they are precisely because they are in the EU.
As for EU growth - I know the EU and Europe aren't the same thing, but the only continent whose economy is growing slower than Europe's is Antarctica's. When it comes to the Eurozone (which Britain wisely decided to stay out of despite the efforts and pleas of Europhiles), only two member states recorded recorded an annual growth rate of 2% or more between 2012 and 2015 - Germany and Spain.
The EU has been economically stagnant for a long time. It's an economic basketcase and it's EU policies which are stagnating its member states' economies.