> Will you move your whole social life with you

A small price compared to dying in war. I'm not saying it's the right choice, but if you have no attachment to your country and people beyond it being a comfortable place to live, that's the choice most will make.

Let me present you an alternative. Europe can build up a credible defense capability which will provide a strong deterrence to Russia. In that case you don't have to die in the trenches and you don't have to spend your life running away from the aggressor.

Nazi Germany did not invade Switzerland, USSR did not invade Finland (after suffering horrible losses in the Winter war), even though both had their own claims on them, because the costs of such an adventure were considered too high. A big part of this deterrence was a population willing to fight to defend their homeland.

it's a bit more nuanced: https://en.wikipedia.org/wiki/Finlandization

Also of course the USSR did invade Finland but got stopped before they could take that much territory, maybe a bit like what will happen in Ukraine.

Not at all like in Ukraine, winter war ended because ww2 started, though you could also see it as the beginning of the same war

> Nazi Germany did not invade Switzerland, USSR did not invade Finland

To be fair these aren't exactly the most relevant examples. On paper the balance of power economically (and military to a somewhat lesser degree) is certainly on the side of the EU/NATO. It would be relative pretty cheap to invest enough just to deter a second rate country (besides nukes) like Russia.