Godless Europeans aren't having children because they enjoy holiday and indulging themselves. Raising children is work - it conflicts with the joy of being a 50 year old teenager.
The problem is they need workers to pay taxes so the State can take care of them when they're old. And pay for their health care now...and pay down the debt - all that borrowed money used to support a lifestyle they couldn't afford.
The 'children' coming up are Muslim. Muslims have children. Indulgent Europeans don't. In two hundred years Europe will be Muslim - and German and French will be a dead languages.