Salaries don't tell the whole story for an employer because you have to pay many more charges on top of the salary. For example in France, the "charges patronales" are about 60% of the salary before taxes. In the UK, the National Insurance contribution for the employer are lower but it's always higher than in the US if I remember correctly. When I compared hiring in France vs the US, the cost was just slightly lower in France but not by the amounts shown here.

For the employee, the salary is obviously much lower than the US but then they also don't have to save for uni, medical care, retirement etc...