I think that it's as simple as this: You get what you incentivize.
There are literally dozens of reasons not to start a tech business in Germany. The taxation structure is brutal, funding opportunities are absurdly conservative, true equity in even early-stage ventures is taxed in Byzantine ways to such an extent that companies award virtual equity (VSOP, lol) which is taxed as standard wage income at payout (45%, lol), and I could go on all day. All of that just barely scratches the surface, but I don't want to write you a book.
Put it like this: You've probably heard that from 1990-2020, VC would look askance at an American entrepreneur if he didn't incorporate in Delaware. "You'd have to be pretty stupid to incorporate your business in New York or New Jersey or something," is what they'd inevitably think to themselves. "What's wrong with you, kid?"
...Well, yeah, incorporating in Germany as opposed to literally anywhere else in the EU is 1000x worse than that.
So you got major brain drain from Germany, where anybody with a modicum of ambition moved elsewhere. Most of those who remained are dyed-in-the-wool wagies, who don't mind using fax machines, and want nothing more than to be salarymen at Philips or ThyssenKrupp.
I expect all Germans will agree with me.
A personal reminiscence somewhat related to digital tech.