My guess is that, to the extent that there may be consistently profitable traders who actually use "indicators," their success is more a function of the other elements of their trading strategy rather than the indicators themselves. I'm guessing that the indicators serve as rather blunt filtering instruments and/or crutches/security blankets that could probably be done away with on careful reflection without materially degrading the trading strategy. Bottom line, I'm guessing that the indicator adds little if any value to a successful trading strategy. Therefore, I'm further guessing that people who rely solely on indicators with no additional "value added" on their part, are probably not profitable.
P.S. Hypostomus, thanks for the heads up on the Camel filters.

P.S. Hypostomus, thanks for the heads up on the Camel filters.

