It could also be that they see no scenario ahead where they want the average number of children per woman to be above 3. I don't think China wants back to exponential growth ever. They probably want to find their equilibrium.
Consider if something unlikely happens that completely changes the dynamic of families, e.g. a cultural shift where women stay more at home and have more babies. If the average family started having more than 3 children, they would consider bringing back this system, which could cause big social problems, as it costs more social capital to bring back an unpopular system than to simply maintain it.
Consider if something unlikely happens that completely changes the dynamic of families, e.g. a cultural shift where women stay more at home and have more babies. If the average family started having more than 3 children, they would consider bringing back this system, which could cause big social problems, as it costs more social capital to bring back an unpopular system than to simply maintain it.