On top of that come Europe's minimum vacation requirement of 4 weeks (although in practice, most are at anything from 24-30 days / 5-6 weeks), the unlimited sick days and numerous national holidays. Also, we have mandatory contributions for pension, social security, healthcare and (in Germany) workplace accident and elderly care insurance.

All of that needs some form of accounting on the employer's side that drives up the gross employment cost.

Or, to put it bluntly, us Europeans tend to see lower take-home amounts on our paystubs for the same gross cost the employer sees on their bank account, but a lot of stuff that you'd have to take care of on your own in the US is covered by that.