America is fabulous at wealth creation. But that's a lot of wealth.... I'm old enough to remember the stock boom of the late 90s and back then there was talk about the days of stock busts being at an end (recall we weren't in a 12 year war, the budget was balanced, gas was a buck a gallon where I lived). And then the tech bubble popped, 9/11, 12 years of war, rampant debt, $4 gas, and the housing bubble popped. That's a lot of headwind.
I'm not a doom-and-gloomer, I just recognize that booms and busts are part of the cycle and articles like the one you read are part of the cycle during a boom.
Stick to the historical growth of the market over decades and the odds are your answer is closer to that number. For an individual, a fortune can be made and saved - concentrate on what you are doing. For society as a whole, I am not as optimistic.