I think the disease model is the primary model of addiction in the US because it helps relieve the stigma and hate of the rest of society against addicts, not because it's an accurate model. It's popularized by 12-step programs a lot more than it is by doctors, thus most people that support this model have no scientific basis, rationale, or reasoning for doing so other than it's better than the alternative, which is to see addiction as a moral failing, a failure of willpower, or a character defect. As another post here points out, those are indeed the old ways of seeing addiction, of society to blame and ostracize addicts. That model is also incorrect, mostly postulated by people who are not addicts, have no experience with addiction, and are generally just looking to place blame and hate rather than for a realistic model of addiction.

Personally, I think both camps are wrong and the most evidence is towards addiction being a societal problem, rather than an individual disease. It's easy to underestimate the influence of one's environment on one's actions, but phenomena like the massive drop-off in addiction rates of Vietnam veterans are rather hard to explain otherwise (http://www.npr.org/sections/health-shots/2012/01/02/14443179...). This is a hard pill to swallow in a place like America where it's ingrained in the culture that people be blamed for whatever wrongdoings they have committed, regardless of the utility of such blame, and regardless of the reality of the blame. A lot of people want to maintain a moralistic high ground and many of those do it simply because they enjoy putting others down and causing conflict (usually because they are suffering themselves). How can people with such attitudes ever look honestly at themselves, their own actions, their communities, and ask themselves if some of these things might somehow be responsible for the suffering of others' in society? They can't and they won't.

I do not think any one particular societal problem can be blamed for addiction, but things like poverty, disease, lack of opportunities, exposure to hate, exposure to trauma, etc. are likely culprits. In a country where anything related to the common good or community is eschewed and often considered un-American, it's no wonder that many people find themselves disconnected, alone, and unwanted. Our society not only shuns the poor and different, but even many of those actively involved in building it, people with jobs who are actively striving to make things better for themselves. Teenagers and young adults who don't live in a city are left to their own boredom by parents who may care, but who cannot do anything about the boredom of suburbia. These people often turn to drugs because they're essentially being neglected by their parents, peers, and likely the educational system or simply do not have the means to socialize because of the distances involved. They develop addiction patterns they will rely on as adults. These are just a couple of examples I can think of off the top of my head of neglect, abuse, hate, poverty, and trauma than a huge portion of the population in the US experiences. Certainly, not everyone will become an addict, but such extreme societal disfunction is a much more likely culprit for addiction than either the disease model or the morality/willpower model.

Specifically, the disease model fails to explain people who are 'cured' and stop using, people who use for only a few years, people who can stop and use at societally accepted levels, etc. The morality/willpower model assumes that we are in control of all actions, that outside events and the environment have no influence on human behavior, and most ridiculous of all, that humans act in a rational matter 100% of the time (silly Kantian ideas). The failings of both of these models are so egregious, I do think it's time to retire both and start to seriously study addiction scientifically rather than provide explanations that we have been pre-conceived ahead of time and fly in the face of evidence.