yes but when all 100 people are bringing in the crops, or training the next batch of soldiers, or working in the steel factory, no one has the time to be trained as an elite fighting force, or build a state of the art robot (or learn how to do both of these things).
The numbers aren't like civ, where they represent the faceless thousands and millions, these are small towns and very minor cities, you need to have people who are free from the daily toils of survival and production to reach the 'high-end' industries and systems that we take for granted today, and that are a given in civ.
I do think I need to increase the costs of some of the stuff in the game, especially the early mid game and beyond.
Not so much the techs, they may be ok (I need to look more at the AI's performance because they are not growing like I think they should, or in comparison to me).
In FTTW, we need the right amount of both popprereq and production, so that high end units and buildings take sufficienty long to build, but also that they are not available to a group of struggling farmers eeking out a new city who suddenly drop everything and to go make a combat robot.
The fact is we will be doing both, to get the balance right. One is not mutaully exclusive from the other.