* Making $1 in the US != making $1 in the EU: There are all sorts of things built into the society here that simply don't exist in the US (or Cali anyway). For example, in Cali I was absolutely required to own a car, which means paying registration and insurance and fuel costs. Here in Dublin the public transit is good enough (amazing from my standard, but don't talk to a German about it) that I can get around perfectly fine without a car. So that's something like $10k/year that I don't have to pay.
* School/University: This is a big one. When I graduated from a California State school (great education, fairly cheap), I had about $25k of student loans to pay off (way on the lower end of the spectrum). I was able to pay these all off in the first couple years of professionally writing code, but someone in the EU wouldn't even have to think about that. So there's around $10k/year for the average engineers salary that just literally doesn't exist (not taking into account the stress and economic inequality caused by having a system based on giant loans to teenagers).
* Childcare: Although I dont have kids, plenty of my Bay Area co-workers did, and were paying on the order of $3k/month for childcare. This is absolutely bonkers nutszo crazyness, but it's a fact of life for many in the US. Doing a quick google search tells me (I have no practical knowledge here) that childcare here in Dublin is something on the order of $250/week which although expensive is still waaaaay cheaper then what you would be paying in California. So here's another $20k/year price difference between the US and EU.
Adding it all up, cost of living here is something like $50k/year cheaper then in California (without even talking about house prices), so getting paid $50k here you're going to be seeing roughly the same value as someone making $100k in Cali and although it might shock some of the hackernews crowd, not all US programmers make $100k/year! I havent done an in depth analysis, but if you look longitudinally across all costs, I would bet that the average software engineer in the EU is being paid in more value (not $, but life value) then the average engineer in the US, especially since people here (on average) report having much higher levels of life satisfaction, and live longer.
Exercise for the reader: I have a friend that recently took a huge pay bump to move to the Washington are and work for Microsoft. He just paid $1M for a 3 bedroom house. What does $1M get you in the EU? Is he actually making more value by taking that job, or is he effectively paying microsoft for the pleasure of living in Seattle?