This was true and tested before IT.

If "before IT" is something like 1960, them, well, the world population was 3B. Also check the levels of deaths from starvation and from infectious diseases, and the cost of food.

No, moving the right "papers" with high speed has made a serious difference.

I was intentionally vague. People seem to read some opinion in it? (given the up and down voting) I have no idea what it means, its just an interesting fact. All I know is that doing it without moving paper was much harder before computers. I didn't mean to say: Because lobsters couldn't do it neither can we. Nor: We have computers now, everything is easy! IT just dramatically changes the puzzle. Not sure we should try history based prediction.

Unfortunately we know how to make more people but not necessarily how to restart a first world economy. And losing old "non-contributing" demographics is much less costly than the young which delays economic consumption and growth by 20+ amount of years to raise and train. It's crass to mention, but these are real considerations. It's down to: you can't work if you're dead, versus you can't work if modern society breaks down and you're dead anyway.