I suspect these statistics are wildly over-optimistic and I have to wonder how they defined the respective groups.
I am a UK-based spread-better mostly in forex and indices. The SB companies here have said for years that at any one time they have only 20-22% of clients profitable.
For me the reasons for widespread failure in forex are -
1. high percentage of account risked per trade
2. chasing reversals instead of following price
3. impulsive day-trading
Most traders are working hard to wipe themselves out, they have nobody else to blame.