Is that unique to the US? It feels like something broadly true if I believe what I see in the news and online forums, but in my personal life it does not feel true at all.
On the other hand, I've talked to a lot of other immigrants who lived in different states before this, and the general consensus (in that admittedly small sample) is that the US is definitely different from South America or Europe in that sense.
For context, I lived in Chile before I moved to the US, and Chile is the country in South America that tries the hardest to be like the US. Even in Chile, it's easier to have a richer social life than here, despite longer working hours and longer commutes, which both result in having much less free time. My own theory is because you get to socialize more at work and, if you have a kid that goes to kindergarten or school, with other parents. Here? "Not so much" would be an understatement.