The bearing of a child takes nine months, no matter how many women are assigned.
For the human makers of things, the incompletenesses and inconsistencies of our ideas become clear only during implementation.
Conceptual integrity is the most important consideration in system design.
There is no single development, in either technology or management technique, which by itself promises even one order-of-magnitude improvement in productivity.
---
These ideas still apply very well to modern society. but, Personally, I hope science advances to the point where nine women really can have a baby in parallel.
We may need that to prevent demographic collapse and keep the pension system from running out of money.
Once we ditch our centrally controlled economies perhaps life can be affordable enough to not prevent willing parents from having children.
It would probably be more practical to make old age less expensive than to inject more people into the bottom of the demographic pyramid. Those young people eventually get old too. I am looking forward to my sentient robot caretaker:
“Open the refrigerator door, HAL”
“I can’t do that right now”