They got millennials from post-Communist countries after all transition periods for new EU members have passed sometime around 2011. Were already lucky because they didn't open the market straight away in 2004 like Ireland, UK, and Sweden. Germans were overconfident because their largest demographic boom was in their 40s back then.

Treated that immigration wave like shit. They left.

Germans worked really hard for every single nasty thing which is about to happen to them.