given the amount of management sim fans
Thing is, I like management sims of various sorts, and I like Elite Dangerous. I'll happily play either for hours and hours.
The X series, which is pretty much the closest hybrid of the two in existence, I could never get into. And I think that was because the cockpit of a spaceship gives a terrible interface for running a galactic trade empire, while the empire-building just gets in the way of flying the spaceship.
However, another problem is...
depending on npc level they fly certain amounts of trips per day (in open)
...instances only exist if there's a player there to observe them. So in most systems - especially the ones which get a real player visiting maybe a couple of times a day (or a couple of times a week...) - there's no instance for this NPC to fly through.
So most of the time it would have to be done abstractly - the game rolls some dice, if they come up higher than some threshold based on the NPC's combat rank and outfitting, and the security of the trade route, you lose the ship, otherwise it gets through.
But there's also another problem, which is that large ships are really expensive and small ships are really cheap. This causes balance problems already, but they're somewhat mitigated by you only being in one place at once, so even if a T-9 is far less cost-effective than a Hauler, it's still more effective for you to fly the T-9.
A fleet of cargo-only haulers will cost you ~70,000 credits per ship with a capacity of 26t each.
A T-9 at 790t costs 84 million credits minimum.
So for the price of a basic T-9 you can get 1200 Haulers, with a total capacity of 31200t (about 40 times the T-9)
Trading Ceramic Composites (several other goods are also suitable) you can buy at ~100cr/t in vast bulk and sell in the right place (which there'll be enough of that you can pick a nearby high-security system) at 10,000cr/t so your initial investment for the Hauler fleet and cargo is still under 90 million credits. On a fully successful run, taking maybe 15 minutes, their cargo would sell for 312 million credits. Don't worry about the trips per day limit on any individual ship's crew - just invest that 312 million in buying another 3600 haulers and their cargo and crew, and repeat. You'll probably lose some of them, but they're really cheap to replace and then you don't have to pay the crew.