You're also dealing with a labor market that punishes people who actually take their maternity/paternity leave, or who actually leave the labor force to raise c

You're also dealing with a labor market that punishes people who actually take their maternity/paternity leave, or who actually leave the labor force to raise children, by simply never letting them back into a career-track position ever again. So not only does 180€/month not substitute for a second salary, it doesn't substitute for the permanent hit to the second wage-earner's career caused by raising children. The economic message is clear: raising children is intended to be a low-paid, part-time job done on top of a full-time career for economically non-valuable warm-fuzzies.