True, there's plenty of underlooked opportunities out there, if we aren't fixated on just one thing. Even more so if you have a carrier.
A few days ago I was unlocking the corrosion resistant cargo rack in the tech broker at Ceos. I peeked at the mission board and noticed there were tons of "fetch" missions for land mines, each paying around 2/3 million but for very small quantities of land mines (from 30 to 70 each mission). I promptly accepted all of them then jumped my carrier to a planet with a base selling land mines, did 3 short roundtrips to load land mines into the carrier using my T-9 cargo loading barge, then jumped back to Ceos and started dumping the land mines though those fetch missions. As I completed them, others kept popping up, and I kept accepting them and completing them, until I had exhausted my hold of land mines.
This can be applied to any commodity that becomes highly in demand through fetch missions in the appropriate states. You can just load up on those commodities beforehand, and then dump them through fetch missions.
In between, some "mine osmium" missions also popped up, which I also near-insta-completed as having a carrier with storage space means I can keep around a stash of "byproducts of mining", such as Osmium or Platinum, instead of throwing everything away to make room for more painite. Dumping these through the mining missions that pop up also makes for much more profit than selling it to markets, making for a nice little side earner, without nay additional work.
An hour and a tad later, I was ~120 million credits richer, took me 2 carrier jumps, and 6 miniscule T-9 roundtrips, and I wasn't even looking for making credits in the first place, I was just going to unlock the corrosion resistant cargo rack. Could have made much more if I had loaded more land mines onto the carrier.