Circular logic. What do you think "discipline" is? It's just a word people use to describe people with strong rational, goal-oriented behavior, with ability to follow through over long periods of time.

This is also called "executive functioning" and it's wholly dependent on your brain chemistry, i.e. the thing that is malfunctioning in addiction.

So yes, they lack "discipline" because discipline is also physiological, it's not just (and maybe not even primarily) a reflection of the person's character. By treating them as separate you're engaging in mind-body dualism.

The impression I get is that it’s even harder than quitting opiates on average, given that many addicts who’ve quit other substances still smoke.

> Its not a black or white situation.

How is it not black and white? You say "it's easy for everyone", I say "you're wrong".

If I'm right, you're wrong. If you're right, I'm wrong. It can't get more black and white than that.