I don’t know about other countries but e.g. in germany the law all but forces you to fire higher performing people before lower performing folks, with additional protections for especially unproductive employees. And that’s for when your business is sufficiently struggling to justify layoffs under the law.

The US hire-and-fire approach is then the other extreme.

The optimal amount of worker protection is somewhere in-between.

The optimal amount of protection provided by businesses is none. Employees are like any other costs, that may need to change based on supply and demand.

The government should be providing protection, by way of providing education and welfare to support reallocation of labor, and taxing businesses to do it. Requiring each business to do it and then policing them is far less efficient for all parties.