i just read the actual article. it's a slightly different spin on dunning-kruger. i know too many very smart people who have left a lot of money on the table by being overly "pessimistic." I know too many not as smart people who have made a lot of moeny by being overly optimistic and using that optimism to forge their own path. "Not as smart" is a relative term here (talking Ivy league graduates vs state school graduates). Unlike the conclusion in the movie Trading Places, upbringing impacts decision prowess as much (if not more) than breeding.
That was my take as well. As for the rest of your post, I understand your point. But that doesn't invalidate the research findings.