[onlyrealcuzzo]

The question isn't: Why doesn't everyone want to raise their children in communal living?

It's more like: why does almost no one want that?

There's a big difference.

It should be obvious why not everyone or even most people don't want that.

It's less obvious why basically no one does - especially since lots of people are actually interested in the idea, and there are - theoretically - advantages.