Obviously, I as the employee have to put in the request for that, and it 100% depends on the company if they actually care enough about labor laws to force/enable me to do so.
But ultimately I think it's culture as much as policies. The US, and lesser extent the UK, has a culture of submitting to work over life (as do other countries, so not singling out the US or UK here). In the UK I had to nag people to take holidays and there was usually a holiday crunch at the end of the year when lots of people took time of just because they had to.
Whereas, living in Norway now, the Scandinavian ethic of maintaining a good work/life balance means there's not really a problem of people not using all their holidays. Or work much overtime either.
[0] https://www.admin.ch/opc/en/classified-compilation/19110009/...