first of all, the main reason it will never fill up is that ppl will get killed off.
but why is that so bad? honestly, why is everyone so obsessed with having the explo phase end, or having the galaxy filled up? the explo phase is always the funnest bit anyway. but more importantly, the end of the expo phase tends to signal the end of most of the hard fighting and the most activity. therefore the round becomes more dull after it. filled up systems allow for slightly safer infra booming. if u want to sit around doing that then your a pansy
economies still grow at the same rate, portals still get built, big wars can still happpen. wot is the downside to a galaxy not being filled up?
I was using a metaphor that means God is watching us. You've heard this, there's a toilet on the roof.