This reminds me alot of another book from H. Beam Piper (Space Vikings), The Cosmic Computer. It describes an entire planet where the industry is based on tech mining, as it was once a miliatry staging point in an interstellar war. The protagonists are looking for the crown jewel of the technological remains, said super computer. I dind't get very far yet though, the blatant 50s misogyny is a real turn-off.
Yeah, that may or may not be a direct inspiration for tech-mining. Aaand, yeah, I kind of had to approach the books as a "historical artifact" to get past that stuff - like, they're very interesting, but it's also hard to unreservedly recommend them.
Doesn't that mean you can never decivilize a rich factions colony? Like, you completly control the system, raid/bomb the enemy colony to reduce stability, they just pay a heap of credits and like by an invisible hand, all your destructive effort is undone? Same for the reverse, just channeling credits seems like a boring way to safe your colony.
Maybe something like a expensive "disaster relief fleet" that has to be send from another planet would provide more chances of interaction.
Well, the AI doesn't do that
Right now, it's just a mechanic for the player to be able to do something to save one of their colonies. If the AI did do this, then it'd probably be possible to balance out with costs and alternate demands on credits. For example, does it do that, or does it launch a military operation to defend another system? As long as it's plausible, I think it'd be alright. A relief fleet is a nice idea, though; could definitely go in that direction if it were to get more fleshed out.
(It also wouldn't undo all of the destruction - you may stabilize the colony and prevent decivilization, but all of its industries are still knocked out for the better part of a year, and it may have gone down in size as well.)