Having discipline in gambling is something very rare to be found, most people just start gambling and then they don't get a grip and continue it until they realize they have become addicted and that is only because they have gambled recklessly and spent a lot of time on it.
Some people become addicted to gambling because of the way in which they view it; specifically, when it gets to the point where they are unable to control it any longer. For example, when someone gambles in order to make money or when they observe someone else making money from gambling, some people assume they become wealthy as a result. I have never seen someone who is wealthy through gambling and did not become addicted; the most of the individuals I know are gambling addicts. Imagine sitting down and imagining how money will come their way without working, which is, in all honesty, pretty rare.
And they receive the money, yet it is still used for gambling. I think if they ran another business and made money from it, they would consider starting a new venture to increase their income. However, they have gambling addictions and continue to gamble with the same amount of money, which forces them to return to their previous financial situation.