I think a key difference here is pensions and social security too.
I live in Sweden don't have any lifelong financial planning. I expect to have a decent pension coming from payments made by my employer, not saved by me (I save a little to extend it just a little bit). I expect that if I get sick I'll get by on my public and private insurances.
That is: I expect to have a whole working life where I don't need to put aside anything. As long as I afford my house, car, holidays etc - I'm fine.
There are no future massive expenses such as my own pension, my kids' college or a sudden illness. And that's also at least partially why my salary is so low, compared to a place where the salary would be required to cover an expensive education, pensions, healthcare etc.
> I would rather have 50% higher expenses and 100-300% higher income
I think this is also a matter of culture. With 100-300% higher income you could argue that you can afford to take a month off every now and then, instead of having the 6w paid a german gets. But the cultural difference is that in the US, perhaps you don't. And with a huge income you can afford to take a year off after having a child. But the cultural difference might mean you can't (because management would object) and so on.
To paraphrase you: there is more to econominc planning than the purely economic too. I think americans often focus a lot (perhaps too much) on income and cost, when the real differences between countries are cultural and lies in how much holiday people take (not just are allowed to take), how long parental leaves are, and so on.