I think your comment represents some but not all addicts.
Some addicts are patients in chronic pain/anxiety who inadvertently get hooked on prescribed opiates or benzos. Others are suffering from mental problems and trying to self-medicate. About 10% of the population are born with unnaturally low levels of dopamine, and these people are predisposed to addiction, regardless of their level of social isolation. Peer pressure from friends who are addicts can also lead to to otherwise healthy people becoming addicted. As I have already mentioned, there are plenty of celebrity addicts who are not at all socially isolated. Prisons are full of addicts, primarily because it offers some relief from a miserable situation. Furthermore, the genetic component that you mention has little to do with the video's theory about social isolation being the key factor.
It isn't complex because we make it complex, it is complex because there many factors at play and many different types of addict. The social isolation theory is but one of many, and new theories are emerging all the time.