Social security. Strong protection against lay-offs. University without paying upfront - just because you don't care for it as someone who didn't grow up here, doesn't mean it's not a benefit for the majority. Healthcare at affordable prices. Public transport.
The thing is, you only see your own benefit. And I feel that's a very typical way of looking at life in the US. The state is not here to rob you, but to provide you with a structure to live in that you couldn't have in the same way on your own. Public transport may not be something you need, but what about the elderly? What about the people who can't drive for whatever reason?
What if you have an accident that renders you unable to work? It doesn't even need to be your fault. Someone might loose control over their car and you might get hit. People like that need strong social nets, and people who can work finance them. Elderly people need those. They are often sick (high health care costs) and not longer able to drive (public transport) and if their pension is not enough, the social security kicks in and supports them.
You personally may not be profiting from it right now, but there's a ton of security built into the system for everyone that gets financed by everyone according to their means.
Maybe there already lies another reason for the lower salaries - if you are from a country which traditionally had your company actually appreciate their employees and make them feel valued, and historically you just had to land your job and could expect to stay with the company the rest of your life, you will not be actively looking unless you get laid off. Loyalty on both sides is still quite common where I live.