This is not an "Everyone knows..."
Unfortunately, the major right-wing party wants to reduce immigration and actually remove German citizenship from non "native" Germans with multiple passports.
People who say life here is getting worse or that it will collapse are either dumb or Nazis.
Whether AFD wants or not, immigrants will continue coming to Germany and will eventually be a majority.
"Native" Germans mostly want to experience life and go to Mallorca, not fulfill silly reproduction goals for an antiquated belief that it's a duty.
Germany will become a really European and diverse country in a few decades and this is awesome. Deal with it.