Aloha,
Just a couple of things.
1: There has been no change recently to income in coop or random.
2: Our primary focus is the PvP or "Random" game mode as the majority of our population is focused there.
3: It IS possible to make credits in coop (though not as much as Random) utilizing signals and camouflages. If you made 129k in a tier 5 ship, you SHOULD have been net positive for credit income, assuming you're not using premium consumables, etc, that cost more credits.
Some people have figured out to watch for our sale of premium and learned how to "game" the system (see what I did there) as premium time can also be earned for free and planned for usage around when you want to play, just some food for thought.
All that being said, please do not team damage or kill out of frustration, this is a violation of our EULA and frowned upon.
Mahalo,
-Hapa