It recovers when having 1.1 kids per person on average does not mean making substantial sacrifices in quality of life over your entire life. Since many people will still not have kids, that sounds like 3 kids per couple being affordable in a comfortable, enjoyable, not stressful manner.

Right now you can guess that for many couples, 2 kids becomes close to unaffordable, and 3 becomes nearly unmanageable. Individually, you will see couples choose to do it and even to do it in ways that others both envy and chastise; but overall, it's not happening.

It requires many things to change not just in economy, but in society as a whole. It's not going to happen in a society devoted to growth, that's for sure.