Happiness is not a single metric you can use to determine what is best. The most rewarding lives are ones where you can sacrifice for something meaningful to you. Sacrificing to have a rewarding, independent life without children may not be the easiest life, but it’s definitely not an any way inferior to a “happier” one raising kids. Because of this, that statistic, even if accurate, doesn’t matter. And doesn’t suggest that anyone should go raise a family.

> Happiness is not a single metric you can use to determine what is best.

If you mean happiness is not the only metric, we're agreed.

> Sacrificing to have a rewarding, independent life without children ... is definitely not an any way inferior to a “happier” one raising kids.

In the way that it makes makes most people less happy, it is.