Because it is really helpful for a young person to know that you are protected in case of serious illness, that if you want to have kids, they will be socially

Because it is really helpful for a young person to know that you are protected in case of serious illness, that if you want to have kids, they will be socially protected which means that they will be able to get good education, health care, educational trips and so on without you paying ridiculous premiums, fees and getting into huge debt. It is also really nice to know that the government will take good care of your parents after their retirement. That they will be able to pay bills, travel, get medicare, etc. When this basic stuff figured out, young people feel safe. That said, there is another interesting problem here: when young people feel safe they may become too lazy. And when people get too lazy, society starts to stagnate which is, as far as I understand, a huge problem in some european countries. But that's a completely different thing to discuss.