@ Alex: I would have thought that you buy one ticket then, if you had Salvaging, roll the dice to buy one more ticket or not. Thanks for explaining otherwise. I will test it more, but so far, Salvaging 3 has been a royal disappointment so far, a contender for one of the worst skills in the game (if all I want is more rare stuff).
So far, I am really tempted to put points into the last two right Industry skills (for more colonies and/or stability, and better self-sufficiency and profits). While I do want the most powerful combat monster, that monster needs a home of its own and income to pay for his war machine.
Re: Tech Mining
It has superb yields, but I get Diktat bullies coming after me, and my "Lone Star" faction is not strong enough to kill endgame or even late midgame fleets yet. (My fleet is not yet strong enough to kill the biggest pirate fleets, let alone major factions.) Thus, I have not built tech-mining yet. If player is powerful enough to repel endgame threats, then sure Tech Mining is overpowered. If not, player might attract enemies he cannot deal with yet.
So far, I reached a point that I cannot add more stuff to my colony without it costing money to maintain (and attract unwanted enemies too early if I try to tech mine). I need to finish more bounties before I can build another colony or upgrade my fleet, or at least earn enough money to absorb losses for a few months.