Just lumping everyone into the middle-class based on income alone, always seemed to be an American conceit.
Class is supposed to be able pedigree; thus a king in exile is still part of the aristocratic elite because he was raised as such even if he doesn't have a dollar to his name.
I doubt the EU will survive in its current state. 10 years ago that would have made me sad. There are enthusiasts, but not enough to make it work.
A lot of people desire this to be true, but that does not mean that it is. It is a particularly weird opinion to hold in the wake of the most recent challenge to its continuity -- the Brexit fiasco, with the EU having maintained a united front for more than 4 years, while the UK emerges out of it in a terrible state -- and the worst is yet to come.
The EU is not perfect by any means (what is?), but it is a terribly ambitious project that has been painstakingly built over decades. Every step of the way, someone like you was claiming that it was impossible, that it was surely about to collapse. Well, we are 27 member states strong and we are dealing with the economic challenged posed by COVID better than most of the rest of the world.
If we look at objective measures, such as economic inequality, political polarization or civil unrest, we are perhaps forced to conclude that the US are closer to collapse than the EU. To be clear, I do not desire the collapse of the US. I think that that US and the EU are natural friends, in a world where they have much more in common than what separates them.