It is hard to talk based on rough statistics.
90% fail?, why not 95% or 70%, nobody really knows the exact percentage of people who fail.
Now, what means fail?, into the very short time?, maybe we all do, into the middle and long therm?, many people is succesful.
What most newbies doesnt understand, and that provides them with a very good reason to fail into every time frame they want to, is that there is a certain set of rules which followed conciously can assure a statistical chance to be succesfull into the short, middle and long therm.
Many people gets scared when we talk about winning 8 - 9 %, or above, of our account daily, but they dont get scared, because they know its highly probable when someone say he lost that ammount.
As i said about rough statistics, each one´s method will dictate the probability to make an income, and that income will depend on the method itself, and other tools such as money and risk management as well.
These is a hard business, successfull people is highly skilled and trained and for those who doesnt have their intelligence, we still have the chance to work hard to find a method that fits our own personality. Its not a betting game, its a lot more complex than that.