Military and social production

Since the production sliders are "global" and there is no way to change the percentages for individual star systems, is there any reason not to be ALWAYS building some sort of ship at EVERY planet, regarless of whether you need one or not? If you leave the militay project empty, it seems you are wasting those resources at that particular star system. You can always disband a ship after its built to avoid the maintenace costs if you don't want it. The last game I played I basically had every planet building a constructor when I didn't need something else, and when it was done I used the constructor to either make a new starbase or upgrade an existing one. There didn't seem to be any penalty to doing this, and in fact, by the end of the game, most of my planets had such absurd production bonuses that they were able to produce most anything within 5 turns, and most ships within 1 turn. I had like 50 planets churning out a constructor EVERY turn! I started building starbases in the sectors controlled by the AI and beefing them up with culture upgrades, and they started defecting to me like moths to a flame. By doing so I was able to win a cultural victory without ever firing a shot on another player. It seemed almost to easy. I haven't tried this technique on the hardest difficulty level yet, but I don't see why it shouldn't work there as well. What's eveyone's feedback on this?