Europe is not a single country, anyway, here's what happen in France:
Firing is tedious, but not impossible. Hiring people is easy, but you enter into competition with higher salaries - like the US - for remote jobs.
> Firing easily and hiring easily are two sides of the same coin.
Not exactly, they diverge when firing is made more difficult.
To fire in France you need a really good reason well justified, and prepare your company for the Prud'hommes trial. Of course you could say "but most companies are big and have HR teams and lawyers dedicated to this, whereas the employee is all alone", but that's also my point about big vs. small companies and legal protections
or, depending on the law, you make mechanically easier to form new companies or create more contracting jobs etc
What you're missing is that in most European countries where firing is hard, it's only for medium to large companies
That operates under the idea that employees only change when fired. And that's patently not true.