Tech Mining is a much longer version of looting a research station where player needs to give up an industry slot, pay lots of money, and wait about a year or more before it is sucked dry enough. And most of the loot is vendor trash! They also generate Pather interest. By the time I can afford to gamble with a tech mine, it is late enough that I do not need most of the loot, and the loot I do want will very likely not spawn in the first place.
However, with that said, ruins are useful as spawn points for flashy man's Phantom blueprints and the historian's magic loot, but player does not need tech mining for that loot.
For tech mining to be useful or fun, it needs to do something special beyond coughing up vendor trash or rare loot that can be raided for without much difficulty.
I dunno, it would be easier than raiding a fortified colony, no?
The hard part is waiting three or more months for stability to recover at least some of the -3 per raid so player will not decivilize the world by accident. I guess in case of Culann and Kazeron, the battlestation should be disabled, so I suppose player needs to be able to crush 250k+ bounties comfortably to raid Culann and Kazeron to lower defenses enough for stealth raiding. Culann has too many exclusive high-tech hulls and various weapons. Kazeron has Champion and pristine nanoforge.
For the player who prepares for raiding and does not need to fight the target, raiding is easy enough.