Ordinary well-adjusted people with wealth and belief that the world that you bring your children into isn't a doomed from the start. A lot of 'well-adjusted' people can't afford to have kids, or they don't believe that their kids will have anything to aspire to. I don't want to be rude, and correct me if I'm wrong, but this comes of as any old Dick or Harry should have kids. For a lot of people in the west kids are simply out of the question if you plan to keep your current quality of life. Which is to say nice job! An actually unpopular opinion!
Also, this is the exact attitude a lot of us have an issue with. If you want to be a parent then that's great! I fully support you in that decision and will do everything I can to help. So why can't you support my individual decision to not have children?
My observation you're responding to is neutral as regards providing support. I didn't know that a) you need support, b) that you were looking here nor c) that a sentence with what amounts to a shower thought can so efficiently deprive you of some. I certainly support everyone's decision to not have children while reserving the right to say they're a great source of happiness and meaning in my life.
For a whole host of reasons. In summary, quality of life for those remaining is going to crater, together with some form of social collapse.
Most social insurances (e.g. pensions and welfare) depend on young, healthy, working people paying for those in need. As the population pyramid gets inverted, eventually this will become completely unsustainable. Meaning those who are young now will not be able to benefit from a pension in the future.
Health care costs are going to soar to unsustainable levels. To some extend, this has already happened. Again, old people tend to require health care a lot more frequently - even permanently, usually- than young people. As the population pyramid gets inverted, this means ever fewer young people have to care for ever more sick people. As an example, my country estimates that by 2050 we'll need to spend 40% of GDP and 1 in 3 working people on health care if we want to keep the service level at today's standards. That's of course completely unrealistic. To some extent this is already starting to deteriorate.
Ever fewer people will have to maintain essential services. Think sanitation, sewage, construction, rail services and so on. Again, unsustainable.
The gerontocracy will mean society will become increasingly inflexible, rigid, and stuck in the past. Young people drive change, old people like to keep things as they are. Opinions don't usually change. Instead, they die one funeral at a time.
The economic challenges caused by an aging population will require tough choices. But with the gerontocracy, such choices will likely not be made. Or they will only be passed on to next generations (who get no say in the matter, as they will be too small a voting bloc). Ultimately this will necessarily lead to some form of social collapse.