Currently the market for software developers is very complicated in Germany.
Basically, the answer is: if you have a job, you stay there (at least until hopefully in a few years the job market situation for software developers in Germany improves).
The question should be "where did they go?" - to Switzerland, years ago already.
How do I know? I've met them there. My project of close to 40 people was over 80% German. Contractors overall were mainly German as well.
And it makes huge sense - in the German part language is largely the same where it matters and salaries are much better. Also there aren't nearly enough Swiss programmers to fill all the positions.
If I were German, I would be in Zürich right now, admiring its hideous bare concrete 20-21st century architecture.
Currently the market for software developers is very complicated in Germany.
Basically, the answer is: if you have a job, you stay there (at least until hopefully in a few years the job market situation for software developers in Germany improves).