You are not entirely wrong boom...wealth indeed can be initiated through a transaction. I'm not arguing that part of your answer as incorrect. I'm simply saying there are other ways it (wealth) is both acquired, and generated as assets in private portfolios grow in value as they are managed, sold, transferred, invested into other managed assets or simply held for future consideration or wealth accumulation.
Trump is wealthy. He holds tremendous amounts of unsold assets. He doesn't have to sell any of them to understand his net worth or see the value of those assets grow adding increased wealth to his overall personal portfolio.