I don't wish for this to be confrontational, but I think you may be underestimating how deeply debilitating substance abuse problems can be. I firmly believe that it is a disease and should be treated as such. It also isn't a self inflicted disease like some like to make it out to be. I have friends who grew up in such horrible conditions that it's almost miraculous that they have come out of such an environment and made it to adulthood, although not all of them have.

I grew up poor but from a generally stable family and through both my own poor decisions and some circumstances outside of my control I ended up homeless. I never suffered from addiction or mental health issues and I still ended up on the streets, so I can sympathize with how hard it must be to tackle those issues simultaneously.

I'll agree with you that we should do much more to tackle these issues early on before they turn into more chronic problems later in life. The initial cost would be expensive but it wouldn't surprise me if it ended up being cheaper in the long run.