Well that's why, because you already make very good money here. But the vast majority of Poles, or even other Europeans in even more expensive countries, don't make anywhere near that money, while having much more expensive housing than Poland.

With that kind of money you're living the good life here already so there's no reason to move to the US even for 2x-5x the money as you can already afford everything you could ever need in Poland on your current salary. You're pretty much in a bubble and are the exception, not the rule.

Like I said before, people with good material situation in Europe have almost no reason to move to the US. But what about those on less fortunate salaries with no wealth to their name, who would get a shot in the US for a >10x pay bump?

A childhood friend's dad moved to work in construction in the US(also from eastern Europe), and with the money from working 15 years there he's set for life in Europe, already retired early and in a McMansion back home. There's no way he could have achieved that financial independence by staying in his eastern European country. Not everyone in Europe has the potential to earn 85k/year here, while in the US it's much much easier.

For many jobs, the EU-US discrepancy in pay is insane, and not just in SW dev.