I agree that trade via raid / black-market trade appears to be totally broken, lol. I tried it out, and yeah, it's pretty easy to rack up a million credits. I don't prefer playing this way, so I didn't comment on the last version, but this time I gave it a go, and it took about 6 months of game-time to ramp up to what would have been Escobar in Spaaaaace.
ideas on How To Fix:
1. IRL, governments that strongly suspect you're a massive drug smuggler freeze your assets while investigating. Having something trip when they're finally on to you, where you suddenly lose access to your bank account, might be amusing.
2. Governments who convict you of smuggling take your ill-gotten gains (i.e., the credits aren't just frozen, they're perma-gone). Plus, if they can, they'll arrest you (send a fleet capable of catching and killing your fleet).
3. Criminals you deal with should happily sell you out to annoyed governments, send fleets of mercs to kill you off, or use hackers to steal your money. Docking at a Pirate base, as a high-end criminal, should be pretty gosh-darn dangerous!
The general lack of consequences, so long as you leave your Transponder off and use stealth ships, doesn't make a lot of sense. People would at least, you know, hear about you, because you're arranging million-credit drug deals. This isn't criminality on such a small scale that it'd just... be ignored, lol. IRL that requires bribes paid, banks to launder the money, rivals that want to turn you in or kill you, and constant danger of being removed by your "associates", because they want the profits for themselves.
Last thoughts:
1. We already have a great example of a criminal money-sponge event. The more money you accrue, by any means, the more of a constant target you should be for Pather fleets that will chase you around and ask for, "donations", heh. Seriously, if they're allowed to spare me when I was investigating one of their lairs 15LY away from civilization, they should be able to hunt you down when you're in the Core.
2. Transponder Off shouldn't mean that nobody identified you doing business. It just means no fleet or large-scale forces were deployed to intercept you. Unless you're literally flying around space-subs full of drugs, the best way to arrest you is when you're docked and helpless; having to fight your way free from a drug-deal that went bad, or to keep the local police forces from arresting you, sounds like risk and entertainment, and it'd be pretty easy to add in as a mechanic.