I think we all ought to be careful about too much generalization on this issue, even as I confess to painting with a pretty broad brush myself!
John C. BogleThe historical data support one conclusion with unusual force: To invest with success, you must be a long-term investor.
John C. BogleThe fund scandals shined the spotlight on the fact that mutual fund managers were putting their interests ahead of the fund shareholders who trusted them, which had much more substantial consequences in the form of excessive fees and the promotion - as the market moved into the stratosphere - of technology funds and new economy funds which were soon to collapse.
John C. BogleBut whatever the consensus on the EMH, I know of no serious academic, professional money manager, trained security analyst, or intelligent individual investor who would disagree with the thrust of EMH: The stock market itself is a demanding taskmaster. It sets a high hurdle that few investors can leap.
John C. Bogle