One story probably sums the total of my knowledge on this: when John Templeton was in his 80s, a billionaire, had been crushing it for five decades, he was rese

One story probably sums the total of my knowledge on this: when John Templeton was in his 80s, a billionaire, had been crushing it for five decades, he was researching the effect of planetary cycles and horoscopes on the market. I know a few people who managed money with him in Nassau at this time. He wasn't senile. So what was he doing? He was willing to test his beliefs...about everything. He could put aside everything he thought he knew even after five decades of success and ask one simple question: what works? Now ask the 30-year old BSD "crushing it bro" dude with the CFA and name brand fund manager on his CV about horoscopes. He will tell you it doesn't work but he won't be able to tell you how he know this (in most cases, he won't even understand the distinction between his thoughts and reality). Most people in the industry know all the facts. They act very professionally at all times when talking seriously with the peers about their many opinions (none of them tested). They don't look at history, they don't look at what works, they don't look at their own decisions (usually, some good funds impose this on managers), they can't think creatively about risk, and they don't know the one or two facts that are important in a big woodpile of information. One answer that history suggests, in addition to the above, is that this always occurs. This has been happening for hundreds of years. But no-one cares. This time it is different, I am special, I am unique, I have been chosen, etc. (if anything, changes in attitudes have made this thinking even more pervasive...young people are even more individualistic and education institutions generally encourage an indulgent self-image). Btw: I have (unfortunately) read most books about investment. I am aware of only one book aimed at investors that actually looks at this effect at large (i.e. what is the relationship between technology and markets? why actually works? what has happened in these situations before? etc.): Engines that Move Markets. One book. A million books about speculation and bubbles...but how many books about actual markets, actual technology, and actual investment...one. The closest is possibly Capital Returns and Capital Account from Marathon...but this is really just a narrative account of two decades. In terms of a "big theory" historical view, there is only one book. That fact alone should demonstrate how utterly disinterested the industry is in anything approaching knowledge (so none of the questions that you pose really matter...no-one cares).