So, I have lived in Frankfurt for a couple of years now, and after talking with so many other expats, I think I have come up with a solid reason why this happens and why I am also thinking about leaving Germany. My TLDR is that Germany makes it really hard to settle down. When you are a skilled worker and you decide to come to Germany, you feel that things in your home country are holding you back, so you move here to step up, to upgrade, to move forward. And that is not what you find here.
- You drove in your previous country? Good luck getting your driver's license in Germany (I know people living in the Netherlands and Italy who have been driving since their first month there), and good luck paying so much for parking. And then, you might say: "but use public transportation". And I reply, good luck going for a dinner with your gf when it 0 degrees outside and raining to get the metro that has less availability (because it is evening already) or they are doing some maintenance in the line. In my experience here, public transportation is only good when is working hours. In Frankfurt, after working hours they reduce itinerary of a metro and during weekends - hahahaha - you would cry with me.
- You want to buy a house? Good luck finding a bank that wants to finance you without a credit history in Germany (a friend already bought a house in the Netherlands, btw). Want to rent a place? Good luck finding someone to rent their house to someone who just arrived in Germany.
- Do you have doubts or problems with bureaucracy? So cute... good luck with that too. Workers in public service do not speak English, and those who do don't want to speak English with you (and that is with me living in Frankfurt - one of the most international cities in Germany). Not even in the Ausländerbehörde do they speak English. (I am ok if the waitress in the cafeteria doesn't speak it, but not in the Ausländerbehörde).
- Then you think: "ok, let's learn the language...". Germany is the most expensive country to learn its own language that I've ever seen. I studied in France and they were teaching French for free there. All the free/cheap German courses here are not for skilled workers, because with a skilled worker's wage, you are above the threshold for social benefits and all the cheap alternatives are out of the question. Then, you might say: "but you can learn online". Fair point, but how do you expect people to connect with your country by learning online? For me, it was way cheaper to pay a professional teacher in my home country online to have individual classes than to attend a German class here.
- You have a problem in your house? Good luck waiting years for it to be "solved". I have full experience with this: we had an issue with the roof of the building and it literally took them more than 2 years to solve it. Because the roof belongs to the building and not the apartment, it is not the landlord's responsibility, and you need to find out who is responsible for it, etc.
And, on top of all this, Germany is not a cheap country to live in, and the infrastructure is far from ideal: trains are always late and expensive, and you cannot rely on DB anymore. Internet is super expensive and slow (we have a bunch of data centers in Frankfurt, but you have no fiber connection in the houses here). Energy is stupidly expensive now (due to German politicians eating shit for breakfast).
So... overall, I think skilled workers think about leaving after some years because small issues stack up, and in the end, you are not able to build a life here. And I don't even want to get into the topic of making friends here, maybe in another post.