Very well said and I completely agree, and I also remember making an example that is somewhat related to this which you have said.
In one of my previous comments on this thread I believe, I talked about someone being sick and clearly needing to receive medication, people around can see that this person is sick and needs medical attention, but the person in question refused and insisted that he or she is not sick, treatment is not something that can be forced on a person except when that person is completely down and can no longer help him or her self up.
Same also goes with all forms of addiction, not just gambling addiction, just as you have said, a sick person have to first agree that he or she is sick and needs medical help, then he can either call the doctor to come check on him or her, or he or she can visit the hospital for check up and possible treatment, same goes with addiction, an addict who has refused to accept that he or she is addicted and need help, will likely remain an addict until he or she first agree, then seek help to come out of it.
This is pretty much the key to the recovery. First addict needs to accept that they might have a problem, after that, only really wanting to take control will give control. Sure, people can do interventions and make someone realize what has he/she done, but they need to really want not to play more then wanting to gamble. It's weirdly simplistic, i know, but that's where the motivation comes.
Also rewarding self-discipline of sticking to the plan can wire your brains so that you get more dopamine rewards from self-discipline than you could from gambling. Or least you can feel so.
I've quitted booze and cigarettes by hating how the addiction has control over me. I just wanted to not smoke and drink more then i wanted to give up on those again.
Same way i got my gambling in control, i hated that i spend more than i planned. I hated the feeling even if it wasn't much.
After a while i accepted that i can't play big bets. I need to focus on reality and budget. Even if i would win big sometimes my budget couldn't handle losing more then planned. I know i am missing out some serious potential profits, but it is what it is. I get to bet bigger only after winning enough.