The biography makes the point that he could not make money in stocks after the SEC was created.
You are trying to make it that he only used inside info, and that is not true. He consistently beat bucketshops, and that was as hard to make money as it gets. He was one of the biggest TA trader too. There is a reason he used chalk board kids to keep the prices fresh on his "monitor".
His inability to make money in later years can be contributed to lots of things, even being burnt out, not necessary for the existence of SEC.