Switching the job too often is a red flag for many companies in Germany.
The system in Germany is based on the idea that it should both not be so easy to quit your position at the company and for the company to fire you (cancellation periods hold for both sides).
I am not so sure whether it's about "skilled":
If you want a fast career, Germany is likely not for you. On the other hand, if you simply want to apply your great skills in a job, I wouldn't say that Germany is a bad place: I would even claim because the skills are much more appreciated by companies in Germany, the system is rather centered around that you tend to stay in a position where your skills are of a lot of use.
So, I am certain that it is not about "skilled", but about "having the expectation to rise up in some arbitrarily set up career ladder". This is something very different from being skilled!
If you ask people, the majority would probably be happy staying at the same job, but getting better paid as they become better at the job. You can do that without having to set up some career ladder, and a lot of smart companies do.