But then who are you buying the ships FROM?
I'm a newbie, but I looked at this as buying the ship's from the private sector, i.e. Boeing or Rockwell Collins. You can even issue bonds and buy the ships with future debt attached to them, i.e. the other options with a lower initial cost but with costs each turn for a specified number of turns. When you build it, I'm assuming that you have a government which owns the means of production.
Of course this is also an economy in the year 2225, so who knows what kinds of advancements/declines in economic thought, resource ownership, etc. might have taken place.
Bottom line though, from what I can tell reading the forums and playing the game a few times, is that there are many ways to conquer the galaxy. One can focus on research, manufacturing, economy, defense, or use a combination of the options available. My first win in GalCiv2 was an influence victory. I don't think my strategy in that game would work with tougher AI opponents but it was interesting to push the borders of influence of one of my opponents so that there own planets weren't even in their own sphere of influence.
I found it interesting that the poster above who knocked the game didn't tell us what he was looking for in a space strategy game and what game he felt met those needs. I question his motives for posting on this board when he has only negative comments on a forum that is designed for those that want to learn how to better play the game. Does he work for a competitor? Or does he just have a need to be negative about things and feel superior about his own tastes?
Anyway, thanks for everyone who posts good tips, strategies, and helpful hints as well as those who answer the questions from those of us who are just learning the game.