this is true but less and less so… I am European living in the US for the last 30+ years. spend my summers in europe and noticing each and every year that this culture is slowly dying. playgrounds where hoards of kids used to be are mostly deserted, mobiles and social media are slowly taking over the lives of europeans too. this may be difficult to see if you are not looking hard cause european cities get A LOT more tourists than US cities (tourists are on their phones too :) )
I have no doubt that materialism and consumerism is eroding social life in Europe too. My point is primarily that the US is way ahead of the curve on this, and it explains much of the difference.
I have a lot of friends who went the opposite direction of you, and chose a cheaper but more fulfilling life in Europe.
Instead of making 200k a year in the us, they make modest salaries and rent 100-year-old farmhouse flats that Americans would call a slum. They drive economy cars and spend their ample time socializing or outdoors.
My personal opinion is that Europeans simply place a higher priority on social interaction and incorporate it into their daily lives. Many of them have more modest financial aspirations, and don't expect to ever own a house, vacation property, or boat.
I basically explain this by comparing my life (US of A) to my sisters (EU). My sister makes great money - my sister spends ALL of this great money. she lives paycheck-to-paycheck which in US would mean she is poor, in EU she is living large (just came back from UAE, heading to Kenya in a couple of weeks, January Macedonia and Austria…). I make 789x what she does and put away 60+% - been doing this for 25 years now, almost done with working though
This is the cultural aspect.