20T seems more than ok.
Gold @ 10K, palladium @ 13k = 200,000 - 270,000K simply for interdicting equals the whole profit for me running 280T of Palladium.
I don't see a problem.
Have you ever tried piracy?
I mean pirating players. And not just for fun, for profit. Have you made a continued, concerted effort to make piracy, and only piracy, your primary source of income?
I have. I went from 1 to 20 million total assets entirely from stolen goods off players. Traders only see a tiny part of the process.
Pirates need to keep their ear to the ground. Find the trade routes before they're farmed out.
Then they need to outfit their ship. They can't spam SCBs, because cargo space is limited. They can't just recklessly upgrade all components, because speed is vital and every tonne counts. Every outfitting is a fine balance between deadliness and utility
They need to stake out supercruise, sometimes going an hour or more without seeing a player.
They need to survive PvP hungry bounty hunters and NPC cops, all after your growing target on your head in the shape of a bounty.
They need to regularly win interdictions, because losing means losing your prey.
They need to communicate fast, and wait until the perfect moment to start firing: too early and your prey that may have cooperated dies or tries to escape, too late and your prey jumps away.
If the prey resists, you have to shoot out their drives and attach limpets, all while travelling and hundreds of metres a second. You have to choose the exact moment to stop following and start scooping, because get too greedy and ever increasing waves of cops will be breathing down their neck.
All the while praying their target doesn't combat log.
Then they need to scoop quickly and effectively, often while under attack from bounty hunters and the police.
They need to find, and then travel to, a suitable black market system, and avoid the authority scans on the way in, selling for a mere 75% of the good's total worth.
After all this effort, risk, time and danger, you're saying we should be satisfied with
the same profit a trader gets from simply from moving from one station to another?!