Besides feeding the economy (and by that, I mean buying consumerist stuff from large corps) and providing the army with cannon fodder, I still haven’t haven’t heard a lot of good arguments for having these babies. Humanity would shrink (I think this is calculated to start after 2050 or so), but besides those two reasons, does that matter? Where is the foundation of the argument that we must have population growth to…
If you expect x plumbers to be needed in year y and x/2 not many years later (within the span of a plumber's working life), how many should choose to become plumbers in each year? How about buildings and other infrastructure with long lifetimes?
Rapid change makes those things difficult. Don't want random home owners to have to speculate on that, and for some of them to lose their shirts when the population is too low to find a buyer for their home.