The term you're looking for is "surplus". The consumer sees a surplus of value because the price they paid is below the maximum they're willing to pay, and the producer sees a surplus because the price they charged was more than the cost to produce the good. In this economic system both parties benefit. Economic surplus is the thing that is "created" with every transaction. "Surplus accumulation" as a concept doesn't make any sense, and is isomorphic to what you think people are saying when they use the phrase "wealth accumulation." You should update your definition of "wealth".

> because the people trading with you thought the exchange was of equal value, or they wouldn't have engaged in it

If this was true I would have emphatically agreed with you on all counts. But it simply isn't true.

Many find themselves in a position where they have their arms twisted to accept a deal they don't like. Yet they accept for some existential reason or another.

I called out the other kind of transactions the 'no regret transactions' here. https://news.ycombinator.com/item?id=48395058 (erm you were personally named ;)

If a billionaires become billionaire through them, cheers, I wish them well.

BTW, thank you for your service.