Sure you might be able to take $150 of weed and sell it for a profit in AZ. But how do you do it? Do you just pull over a side of the road, throw up a sign that says "Weed, $300 o.b.o.?" You think someone's just going to buy it from you, not knowing who you are, or if your product is laced with pesticide? Or is a bag of oregano?
You might be able to sell it to someone you know, who might be able to give you a good profit. But they're still going to want a cut. And you're still talking about a dime bag of weed.
We're talking about moving TONS of illegal merchandise here. TONS. Shipping containers full, right? The kind of quantity that if you got caught with in real life, you'd go away for a looooong time. And anybody who gets caught with your stolen merch is going to suffer the same price. So, you pull up in your Cobra to a station you've never visited before with 40 tons of narcotics. You think you can just roll up on the deck and throw out your sign saying "13,000cr o.b.o." Anybody who takes it off of your hands is now guilty of a major crime. Dock workers are going to have to be bribed. Customs people are going to have to be paid off. Inspection officials given a cut to look the other way. And certainly, the people who are RUNNING the black market operation are expecting to make a profit by selling it at the higher price.
Do you think captains bringing the product get all the profit? Do they go to the cartel boss and say "Pay me full market value, bitch!" Or do they just drop off their cargo, shut the fuck up, take what cut they have and GTFO?
Your comparison of the Aussie smugglers is not a proper comparison. They were smuggling eight kilos of cocaine. That's like 0.008 tons. They thought they could slip it in. They weren't going through the big boys, and based on how drug cartels work that's why they're getting executed - the people doing that kind of business don't want independents operating on their own.
In Elite Dangerous, you are smuggling metric tons of illegal goods to what can only be organized crime. They are going to take a big chunk of your profits, regardless of what it is.