I come from Spain, and the situation was very easy: Spain's cities have a midwest-like cost of living. A programmer there, right out of school, is what we call a mileurista: Someone with a take home of about a thousand Euros a month. In comparison, my first job in the midwest paid three times that. And that's the difference at the beginning of a career. Nobody programming over there will make more than, maybe, 3500 euros a month, unless they start their own company. Last year, I went past 18K a month, in a stable, 9-5 job. The market is so good, I could quit my job any day I want, and I get to choose among a bunch of great alternatives, including bay area companies that hire remotes. In comparison, Spain has about 20% unemployment.
If anything, I would ask other programmers from Spain why in the world aren't they leaving!
So this plus even browsing job postings around England (which I can do better than job postings in Spain porque mi Espanol no es bueno), this seems generally true.
So big question. WHY are software developers paid so low in 1st world European countries, and so high in the US? Clearly a good software developer can save a company 100k, 200k, 500k Euros a year (think of replacing a bunch of office workers with a computer program). Why don't programmers get a bigger chunk of the pie?
GDP says the countries are fairly similar. Programming is a high skill job. Why would it pay so different in different locations?
If anything, I would ask other programmers from Spain why in the world aren't they leaving!