I agree with the both of you, but something we must also understand is that, lack of discipline in gambling has every thing to do with addiction, it is obvious that gambling addicts don't know what the word "discipline" mean in gambling,.
And as for a gambler who is not addicted to gambling and does not discipline him or herself in their gambling activities, such person is also on the highway to becoming a gambling addict.
So when you say that only 20 percent of gamblers are disciplined , I assume that what you mean also is that. It's only 20 percent of gamblers who are not addicted to gambling, I might not want to believe this though .
Of all the activities that are often associated with compulsion issues, gambling should be one with the lowest rates of addiction, and this is most likely the case because people deep down can control themselves very well when they gamble.
Now a person may lose control once or twice, but they will learn from those experiences and never make this mistake again, after all if the percentage of people which were addicted or on their way to become addicted to gambling was really 80% then we can be sure gambling will be banned by now as it would be impossible to have a working society otherwise.