the_dunk_tank

(i.e. birthrates would return to what they were 100 odd years ago)

I don't disagree with your main point in that "just improve the material conditions it's so easy!!!" is very wrong and there's way too much misogyny thrown around when this topic is brought up, but this part isn't true, I'm pretty sure not a single person on this site wants to go back to a fertility rate of over 3 here (which is what it was in 1924 in the united states), because it would cause massive population overgrowth, the main concern is getting it to (or at least very close to) 2.11 so that the population remains steady. And I do think there's another side to this conversation, in that a lot of people on the left also very much stick their fingers in their ears and insist that dramatic population drops won't cause massive societal problems, because talking about it brings in too many racists and misogynists (bleating about fertility rates has been a racist dogwhistle for decades as well).

For my 2 cents, I don't think this is problem is necessarily insolvable. I think there's 3 main things besides improved economic that could get people to willingly have more kids.

The first is that pregnancy and obviously especially birth just fucking sucks for women and just makes having kids much more disadvantageous for the woman off the jump. Even just the pregnancy can have life changing effects on your body, let alone giving birth. Maybe this is too bazinga tech brained, and is decades if not over a century away, but I think artificial wombs are the obvious solution. It will immediately revolutionize reproductive labor, and equalize the day one burden on women and men. I think a feminist from like the 70s or 80s wrote a book about this one time, right?

The second is that childrearing is still unfair to women. Men still don't take their fair share in reproductive labor even post birth (not to mention home care labor or emotional labor). Additionally, having children (and even not having children!) disadvantages women far more in the work place as they are passed over for promotion due to pregnancy, childbirth, or especially the employer's fear of it. I think this is far more simple to solve, especially for socialist countries, as evidenced by the massive gap between women's participation in STEM between even former soviet-bloc countries and western ones (not that these places are perfect of course). With state-led intervention (idk maybe make all men take "respect women" classes in school would help lol), these problems should be especially solvable.

The last is that there's too much opportunity cost in being a parent. By this I mean you lose out on a lot of freetime becoming a parent compared to being childless, because we don't really raise kids communally anymore. If you're lucky the kid's grandparents will be willing to help, or other close family members. If everyone in society helped with raising kids, this would free up a lot of parent's time, and make being a parent far less unappealing. This is the problem I'm least sure how to deal with, because how do you get people to live communally? I'm very interested to see how Cuba's family code turns out, and I'd love to see something like it implemented in a more industrialized society to see how that changes communities.