I'd work harder too if I'd lose my healthcare after being fired. Americans also do more work in a year because they have hardly any vacation days; technically they've worked more hours.
that is only part of the picture. in my experience being a European in the US what is etched in the culture here is that working “hard” gets you advancements at work which translates to “better life.” that then translates to working crazy hours, answering emails and slack messages from (for the “crazy” ones that take it) vacations etc…