If everybody suddenly stopped having kids, I think a lack of retirement would be the least of our problems. But you seem to feel as if only people who have kids are entitled to retirement, while people without kids don't have that right. And that's very much an opinion, not a fact.

It was the case in the distant past when your kids were your retirement, and even then people tended to work until they died, but that time is now in the distant past. At least in the industrialised world. There may be poor countries where this is still very much the case.