What I'm in disagreement with, is the stance that "as long as one is self-sustainable and does a good job", there's no real problem to it". Now that might not be what you wanted to say, but I think it's a reasonable enough reading of the text.
I have many friends who are addicted to Cannabis, who all have good jobs and do good work. But compared to other friends I feel I can see a certain lack of grander, more personal ambitions. Now I might just be confusing the direction of the correlation here, and Heroin is probably a whole different beast. I guess, I just want to say there's more to life. And some drugs might open certain doors in your mind to deeper meaning, but my (limited) observations lead me to the conclusion that addiction to drugs tends to be more of a door-closer.