So your solution, which is the status quo, is perfectly logical and sufficiently complex. However, my idea, which is to decriminalize and offer treatment is simplistic and built on general knowledge. The fact that it would approach the same costs for incarceration may be true. However, you would remove the rest of the criminal element that goes along with the huge artificial profits built into drug dealing and you lower the price to a point where people (desperate addicts) aren't killing for crack money. You are simply more intelligent than me. I give up.
I do not think change for the sake of change is warranted, and I believe it's prudent to use the old carpenter's rule...measure twice, cut once.
Any answer is going to be less than perfect. I think we have to satisfy ourselves that it's less imperfect than what we have now.
Our current policy is a flock of unintentional consequences. Believe it or not, it can get worse.