Meanwhile people in the US have been framing Spain as some kind of post-work utopia. The "we quit our jobs and moved our family to Spain" is all over social media.
A lot of that is due to relatively low rents by EU standards (even if locals might complain, because their salaries are low compared to some other EU countries).
Not just rent but food and wine are also inexpensive (and amazing). Plus many Americans are already familiar with the language.
If you can work remotely (or not at all), Spain has a lot going for it.
Those are not incompatible though? I'm from Spain and it's a great place to retire.
The railway system in the US is not very impressive, though.
Let me provide some context to that. At the highest levels of Spanish earning or net worth brackets people experience a completely different life than most everyday people. With a net worth of $1-2M you can live in a bubble essentially, living in a gated community with 24/7 security, with a helicopter landing pad. As a wealthy expat you can brute-force most of the societal struggles. Having 1-2M in your pocket enables a life that requires 20M+ in the US.