I suspect the % who didn't have an edge lost a lot if not all their money trying to find one.
It is the only way I am sure of it.
Only way to get to be consistently profitable, by that I mean the point where you make a living from it, is to learn a lot before you put cash down. Either you are lucky and know people who can teach you personally or you need to learn by filtering out the useful information available on the net and in books. Neither way will be quick, research never is, but in the long run you will then have a chance of survival.
I found that the edge is actually very simple but took me a long time to figure that out. Patience and discipline.