Yeah there is really no debate or uncertainty on this topic, it is quite clear, just follow the money: If you can trade for a living (& particularly by using a "system" or "method") why on earth would you give up that uber-scalable printing press to deal with a bunch of random Kooks. Come on. How can peeps be so gullible?
It's not that obvious though, there's a small % of people who have a strong sense of altruism, very few in this business though, more want to minimize their risk by giving themselves a guaranteed steady source of income in addition to whatever sporadic trading winnings they would have the luck and skill to get from day trading.