Players can have a short term effect on the trade networks for that system but it is NPC based.

Each system can be poor to rich. There is even a ship scanner module to see economy for a solar system but I’ve not installed or built it. So I don’t know to what scale that displays information.

Trading is quite an easy thing to take advantage of for a lot of money in the game. I think I was at 1 billion units in under 100 jumps. There are lots of other ways to make money than just buying and selling.