You make it sound like it is very easy to quit addiction. If it was that easy, there would be any addicts in the world. Just learning about dopamine wont make them less addicted or stop them. You get dopamine from lots of activities, but you don't get addicted to those.
That's the key problem there. The only reason they get addicted is because they don't want to change. Those who truly wanted to change was able to overcome their addictions. Others are just a lost cause. You need strong will and a reason (such as having a better future) to get out of addictions. There are people that can never overcome addiction because they no longer have anything else to lose in life.