Birth rates fall as prosperity increases.

That's more true in some locations than in others. There are places where the reported quality of life is quite a bit higher than others. I see comments like yours a lot on HN, and I'm starting to suspect that the average HN commenter is more likely to be living in some of the poorly-run big cities than in the better-run small-to-medium-sized towns. (Specifics can, and will vary. But on average I've found I'm much happier living in a medium-sized town than in a megacity, and I've also found the city governments of medium-sized towns to be more likely to be competent. Perhaps I've just been lucky in the medium towns I've lived in, though; I'd need far more data before I was certain of the thesis).

Point is, if you're miserable in the place where you are, consider whether moving to a different town is feasible for you. It's not always an option for many people, for many varied reasons. But it's definitely something to consider. If it turns out you can do it, sometimes taking that risk can pay off in the long run.