Gotta wonder that out of the 5-600,000 planets out there, why aren't any of them already populated by NPC's? Grumpy ones at that?

A thousand eons ago the all planets of the universe were populated by species unique to their planets. Then Aac'Dac came along, and with Aac'Dac the power of hard rock. Aac'Dac saw that these species were pompous and egotistical, thinking that they were of all that existed in the universe the greatest things evah. Seeing this Aac'Dac pondered, and then through a sudden epiphany Aac'Dac knew exactly what to do! And so Aac'Dac said
"Let there be light, and there was light
Let there be sound, and there was sound
Let there be drums, there was drums
Let there be guitar, there was guitar, ah
Let there be rock"

And it came to pass. That rock 'n' roll was born, all across the land every rockin' band was blowin' up a storm.And the guitar man got famous the business man got rich. And in every bar there was a superstar, with a seven year itch.There was fifteen million fingers learnin' how to play.

And so the planets of the universe came together, recognizing each other's mad skillz of rock and called each other brothers. Then Aac'Dac put it upon himself to then show the beings of the universe the "R" part of rock. (you know, "sex,drugs, and rock and roll") So the beings followed Aac'Dac's way for many generations. Seeing his work was done Aac'Dac left, forgetting to teach the being one very important thing....

By this time there was no one left who opposed the ways of Aac'Dac and thusly there were no scientists left, except one. He was know as "Darth Chewy". Then out of no where everyone became sick, deathly sick; but no one knew what to do. Everyone was sick in some different fashion and no matter how much medicine the sick took they died. Darth Chewy saw this epidemic among his people and worked franticly to put a stop to it. After years of testing and studying Darth Chewy discovered the cause. Alien Immeuno Deficiency Virus. As soon as he learned this he tried to find someone who hadn't already caught the virus but to his dismay there was none, not one being in the universe other then himself hadn't caught AIDV. Realizing this he cried, until his very last moment.......

And thats why theres no NPCs in GL.
Aac'Dac's Greatest

We keep discovering the artifacts that they left behind. Being of a nature that the artifacts are all powerful and dangerous, it is no wonder that the previous occupants are all dead. In fact, the Prejor may be all that is left of them. It explains why they developed the Prejor Becon: to hide themselves from what happend to everyone else.