Grail systems. I disagree on one point poker. The idea that if it worked everyone would use it gives way too much credit to mankind as a whole. Think back over the years of your own experience, how many are discouragaed at 1 loss, how bad do they react at 2 in a row? They would 2nd guess any system, be discouraged at drawdowns and chafe if their signal did not get every last penny of a move. Back when my program used to take 5 minutes per day to update, I had more than a few people ask if there was anyway around that 5 minutes work?
Last but not least there will always be 'grass is greener' syndrome.
I say unless it delivered 100% winners almost weekly and delivered a check to their account automatically, no system or method will ever become widespread, no matter how good.
The reason is simple: humans are a flighty bunch.