Whoever said that in Germany people make enough are nuts.
Let's suppose you have 2 kids. If you get a rental contract in Berlin Today, in 2023. The ideal space according to the government and known research is 30m2 per person, you'd need an apartment with 120m2.
120m2 apartments are like 2500 euros per month, more than half of your salary post-taxes. Tenants typically ask for rents to be 30% of your income, you'd have trouble finding an apartment.
Here's why people also don't have kids in Germany, salaries are terrible.
I've been living here in Berlin for almost 10 years. And only after 8 years I could have a decent life here, even making definitely above the market salaries. And by decent I mean, better than my third-world country.
People won't be willing to move to Germany if they'll live in a shoebox and have no disposable income. They'd rather stay home where their parents, family and friends are, save money and speak their local language.
And without Immigrants, given that Germans in general don't want to reproduce because they can't afford having kids, the country's population size will start decaying.
This post-war mindset from a few people in Germany that people need to get paid just enough to buy Bread and live in a shared flat is what is sinking that country.