I think this kinds of research is just pants.

When you ask people these kind of vague aspiration goals. The answers don't change.

Same reason everyone rates Schindler's list 5/5 on Netflix and never watches it. (Paraquoting Reed Hastings).

The biggest factor imo is that these days people have better things to do than have kids. Mostly work at jobs they hate.

Similarly everyone prefers to watch an Adam Sandler movie they say they hate and not Schindler's list.