"It wouldn't because it's stationary, and those little squares are actually huge amounts of space. Ever notice how sometimes there are two plants in adjacent squares. Care to guess how far apart they are? Even with one square separating planets, think of how far earth is from mars...
A simpler answer, and I promise I'm not trying to be snide, is "that's the rule." Remember that this is a game, and sometimes things need to be arbitrarily adjucated - it could've been either way, but this way is no worse than another."
I dont agree to u. allthough a starbase is stationary ,it is a huge complexity or better to say a monstrous mechanism. I dont mention the numbers of turrets and the rocket launchers... and most of the scifi games are using the starbases as massively forts for planetary denefse.even in moo3 is the same.starbases are planetary defense and it couldnt make any sense when it couldnt fire to enemy troops passing by. this is like an armada is attacking the planet and the guys in the starbase are watching them passing by and do nothing "mars colony...mars colony this is starbase 13...I see a huge armada of drengin ships towarding to u...ooo damin theyre pretty tough...this time they gonna kick yer asses badly... I wish u guys good luck..." "what arent ye gonna help us ye damin? for what did we put ye tuff upther?" "hey its not up to me! we are jus starbase!..." "you...crash... bum...scream...deadly silence" "god save ur souls brother..."