> exceptionally good life in Poland

Compared to your environment, sure. However, you'll never drive a Tesla and buy $4000 road bikes when you're on $27k/y.

> Just because a software engineer in SF can make $100k/year doesn't mean that's what the position is worth

It means exactly that in a free market capitalism (and while we're not living in a pure free market, we're not _that_ far). Why would a company overpay? (Sometimes they do, but not 4x, and not consistently.) In case everyone's massively overpaying in SV, then you could just start a company there and pay people half the salaries and be extremely competitive.