Let’s just be simple about this: pensions and oth3r old age support. Who pays for those? Young people. If young people have to support a lot of old people, you’re gonna have a bad time. Everyone. The young people have have larger amounts taken out of their pay and old people who get less support because there are just literally not enough resources. And because old people outnumber young people young are pressured more and more under democracy to give more to older people.
That is only one terrible thing from demographic collapse.