It’s not the whole story. Paying people to have kids won’t fix it. We already pay people to have kids. Earned income tax credit...welfare...wick, etc. It’s not working.
Of course it works. We pay the welfare classes to have kids. They have plenty of kids. We tax the middle class up to its eyeballs. They don't have (enough) kids.
The financial penalities aren't the whole story but they're a big part of it. I'd favor a much larger child tax credit but it would need to be targeted to working parents, not welfare, so that it doesn't become an inducement to dependency. In major metro areas where the publick skools are a problem, school choice and vouchers would work wonders. I live in D.C. and private school has become a perceived necessity for the middle and upper middle class. It's a big bite.
The schools and employers need to do their part too, especially on time management. We get run ragged, as do all the other parents, with the schools taking every holiday known to man plus all the random half days and teacher training days, etc. Workplaces also need to adjust. Many, probably most, employers pay lip service to being family friendly but the reality is otherwise. 24/7 connectivity makes it worse. Like the schools, workplaces haven't really adjusted to the reality of two-worker families. I don't have a clue how the single moms manage at all. (A lot of them don't.)
In a thousand and one ways, most of them subtle, societies organize themselves around templates based on ideas of the "normal" or "typical" situation. The normal or typical implicitly becomes the preferred or favored. Today society is normalized for the single or childless person. That's what has to change.
This will take a conscious effort. I don't quite know how to do it. I've often thought that if I were an employer I'd call all the young singles into a room and explain to them that life is a cycle, that most of them will have kids sooner or later, that parents will be treated preferentially, and that their turn will come. I suppose I'd be sued.