There was a recent discussion on Less Wrong about whether or not ambitious people should have kids.

I didn't manage to watch it, though I have a lot of interest in the topic. It wasn't recorded but I can still hope for someone to post lots of details about it in the comments.

One subtheme from the comments that stuck out to me was the idea that there are lots of people who want children (because it would satisfy a genetic urge, or because it is fulfilling, etc.) but delay or decide not to procreate. They hold off because they expect that having children dominates their life in a way which could prevent them as a parent from being able to focus on your work, and this could be a severe limiter for ambitious goals. I certainly resonate with this.

To solve this, I've been thinking for a long time that it would be great if a bunch of families lived together. You'd only require one parent (or caretaker) to watch over a bunch of other people's kids at any moment. Living together has a bunch of other benefits too. It's hard to find big houses (or a cluster) with all the amenities that a bunch of separate families would need, but it is possible to build such developments to spec.

As a proof of concept, Jefftk raises his kids with a bunch of other adults in the house. I don't think his house would be big enough for those adults to have their own families, though.

Why don't people already co-raise their kids with other ambitious families? Well, I think some people probably do, in private situations that we aren't aware of. But it's not widespread. It seems like a really difficult coordination problem, to set up a good situation to raise kids with other families all in one place. You have to solve simultaneously for:

the space needs of all the families, plus any hired help
money: the means to pay for the house (mortgages, rent, etc), wages for hired help if any; plus negotiating loans or room rents across lots of people
whatever location constraints you have (for jobs/commutes/schools/etc)
all the labor of actually finding or building a home (possibly including solving zoning constraints) and maintenance
challenges related to having a bunch of people sharing the same space and presumably working from home, being very busy, etc. (like, there's a normal cooking rotation but someone gets called away and nobody else has enough time to prepare dinner for 12, clean up afterwards,

...