> 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.