People in USA [I assume you mean] are happier and more fulfilled than those living in Europe?

The median American is richer than the median European (in basically any large country).

The SpaceX employees that got laid off are going to get other jobs and continue making more money and having more money to spend than their European counterparts.

Edit: A few reasons. One is that, since it's easier to switch jobs, good employees have more leverage. Another is that, since it's easier to fire bad employees, the expected value of a new employee is higher and you can afford to pay them more.

I think a big part of American prosperity is a result of companies being able to fire people. It's probably the most important bit of employment non-regulation that this country has, and it's a big aspect in which America is more worker-friendly than European countries. Other missing regulations, like working hours limits, vacation time regulations, don't benefit workers as much (or at all).

Standards of living is complex, more of a vector field than a single scalar.

“Western” Europe is on average rich, Eastern Europe is still recovering from Soviet control and brain-drain. But even Western Europe is spikey, old Welsh coal-mining towns are poor, the old universities are rich.

Even apart from the location income variability, what money gets you varies; health costs much less in the UK than the USA, housing is cheaper in poor places than rich places — even PPP exchange rates aren’t perfect because the ratio of two different goods isn’t constant.