Agree and there are many reasons more.
I'll add religion to the mix. We're less religious now. Even folks who are religious now(at least in the Christian West) seem to practice a different religion than we did 50 years ago. Religion does many things, good and bad, but it definitely prizes children and reproduction. If it didn't, it would quickly get replaced by a mode of thought/belief which did. I'm not advocating for religion here, just stating that it likely plays a large role in reproduction.
I go to church. Everyone has 3 kids. Thanks for bringing it up!
Yes, I don't think this is a single faceted issue. I've yet to see anyone here mention animals yet... but numerous animals in captivity have also been shown to have far lower breeding/fertility rates. Factors like restricted space, lack of mate choice, and disrupted natural instincts can all influence animal behavior, and I see no reason why the same can't apply to us?
I know for me personally, it's not economic reasons as to why I have not had children, but more a problem of finding the right mate at the right time. Some people just aren't socially fit for each other...