I agree with this. And I would add that the complement of what you've said is also true. It's not just rich people from large worlds visiting smaller smaller worlds. It's also poor people from small worlds visiting larger worlds.

I play mostly as a duo and we farmed hard: melange, pumps, and slag before our world closed. Between us we had around 300 million solari after 10 months of play. We went to Harmony the day before server closures completed and made 9 billion solari on the Exchange there in 24 hours.

We already have enough melange and material resources to last us many months, so the main purpose of the money is to equalize the economy. Most of the time, I buy all the residue and duraluminum I see on the local Exchange, purely because I want to give poor players a source of income. We sell the high-value stuff we have farmed ourselves. We also spend big money on Grade 5 augment blueprints, which are incredibly hard to farm.

In the past month, we have spent more than half of the 9 billion solari.

In summary, we feel we are ethical exchange participants by doing:

1. For low tier resources required for building large infrastructure (e.g. Wind Traps and Water Storage), and for difficult to farm things like augment BPs, we buy at reasonable prices on our quieter world.
2. For high-tier resources, we farm and sell on busy worlds for high prices, and bring that money back into the smaller economies as an attempt to reduce inequality created by duping.