Oh, I think the total amount of wealth changes. It's not a zero sum market or economy.
While by nature the wealthy do tend to accumulate wealth, last I looked, the vast majority of millionaires in the U.S. were first generation wealthy, and the number of them and the amount of their wealth grows. I don't believe that necessarily means anyone becomes less prosperous, or more impoverished. A large percentage of those who generate wealth for themselves employ and enrich others.