Some gamblers can try to discipline themselves but might not have all that it takes to pull a strong decision, which is where the help of professionals or those who are close to them can come in by providing helping tips for them, and they will take the tips seriously based on how well they really want to get out of the addiction.
You are correct. Many people whom I knew who has been addicted gamblers decided and fought hard to left gambling and months or a year later, I found them again gambling. And there is no much different. And the only difference is the time spent before and now in the gambling hall. Before there was a frequent visit but now it is once a week but that once, they would spend enough money and lost them all. So I also noticed that it is hard to leave gambling addiction.
You see that "once in a week" ideology, it's a big trap that many gambling addicts still fall for. The moment they change from spending their days in the gambling hall and switches to once in a week, they think they're in control of their gambling activities but just like you said, they'll still end up blowing up as much money as they would if they're more frequent.
You can only control your gambling addition when you've always been in full control of your gambling from the start, but as far as you're addicted, trying to cut down your gambling time wouldn't change the effect on you. An addicted gambler needs to totally abstain from gambling to actually break the cycle.