> Cost of labor is insanely high due to cost of housing

This is not the reason. Labor is expensive even in parts of the US with low housing costs.

The real, simple reason is the US has a more prosperous economy where the average worker has more opportunity than their Spanish peers. Just look at unemployment rates. The US is at 4.3% right now compared to Spain's 10%. Even at the peak of the GFC the US barely had over 10% unemployment. In the meanwhile Spain has had over 10% employment almost the entire time the past four decades. Of course labor is cheap when that many people are jobless.

U-6 is 8.1%, but spain uses a pretty comparable base employment rate (u-3 equivalent), so fair cop that US unemployment is easily less than half.

Relevant: https://en.wikipedia.org/wiki/Baumol_effect - drives a lot of effects in the US where automation paradoxically makes non-automated industries insanely expensive (though not the whole story for certain niches e.g. healthcare and education)

I mean, if you can have higher unemployment but still build good subways and overall have a good quality of life, maybe that suggests unemployment isn't a great metric for evaluating societies.