Why are parents so predisposed with trying to convince other people to have children as well, especially those who have made a decision not to, either way?
How are those analogous? People can live perfectly fine without a child but can't without a job (unless they live at home with their parents which coincidentally a lot of hikikomori do).
The ability to attract and successfully integrate hundreds of thousands of immigrants per year to support an oversized elderly population is not a luxury that most countries that can afford.
For most communities, normalizing childless will only come back to bite people in some form or another.
