It's a pretty big sacrifice for a woman to even get one up and running, including the risks, pain, and effort of pregnancy, birth, breastfeeding, and rearing (sleepless nights). While working.
And 2 parents handling 2 babies/toddlers without help is pretty intense for at least 5 years or so, both are basically on call. It's not like previous generations where there's a chain of older siblings/cousins/etc that can give you a break (that is apparently the role of Youtube these days).
>It would be super easy if things were even more communal.
Probably, but that isn't reality for many people, especially with economic opportunities and growth getting more and more agglomerated.
>I think a lot of people would prefer to have more than 2 kids.
All the data I have seen indicates that this is a minority opinion among women. All across the globe, all across cultures, all across socioeconomic classes, 2 is where most women stop, especially if they get a boy and a girl.
Up here in Canada, according to statistics, only 20% of couples want to have 3+ children. If I recall it correctly, it’s not that they have it, but plan to, which might not even happen due to socioeconomic reasons.
I don’t think majority of young people want to have 3 children though, as you mentioned. Even if I do an extremely unscientific look around in my circles, the number of couples who want that is 0. I obviously might be in a bubble, but it’s a fairly common sentiment especially for my age group.
Taking care of kids is not that hard or much of a sacrifice really. It would be super easy if things were even more communal. There's just really not that much great stuff that you are missing out on after like 35/40+. In truth most of the stuff geared to people in that age range is designed for people with kids. I think a lot of people would prefer to have more than 2 kids. The major issue is that SO much stuff is designed for the family of four. Yeah there's 3rd row seating, but it's annoying. Furniture that comes in 2 packs, theme parks, restaurant tables, vacation accommodations, etc. Because of modern life and the things we are accustomed to the logistical management burden of more than two children is very significant.