That's not how it works at all. Of course you can fire someone with proper cause, you just can't fire someone __at will__. Lack of demand for the position is proper cause. If you don't need staff you can fire them, but you cannot fire someone and hire someone else in the same position.
What's the argument to not be able to fire someone because you can hire someone with better or relevant skills instead? That makes the business stronger, which means it can make more money, which means it can hire more people.
Well the arguments are many, and the counter-arguments also many. The point of my comment was not say that the (typically European) system is better, but it's not like described as parent commenter where you cannot fire people and are stuck with too much staff. That is not the case. I wasn't really arguing for it being better for the company and/or society.
Relevant skill could be proper cause. You can absolutely fire someone for not having the skills you need and hire someone else with the right skillset.
