Why might we eventually see something akin to a total legalization of drugs?  Because the alternatives are truly intolerable.  Non-legalization reforms of the prohibition system can do immense good for many.  Things such as reducing sentences, lessening incarceration rates, implementing rational harm reduction strategies and offering free voluntary treatment can help a lot.  But what they can't do is eliminate the massive and massively corrupting drugs industry.  
Yes, if cocaine and heroin become legal and freely available, some additional people may use those substances and develop serious problems.  But if that's the only major drug problem in a legalized world, it's a quantum leap above the myriad traumas created by prohibition.  And in a fundamental way, at least this potential problem of additional addicts would be faced foremost by those who have chosen to risk the consequences of drug use.  Who among us now chooses to have their government and police officials corrupted by the narco?  What Colombian farmer chooses to have poison sprayed over his fields and children?  Who but the gun merchant chooses their city to be terrorized by militarized police and heavily armed dealers?  
But I can suggest one reform short of cocaine legalization that would cripple the international cocaine smuggling industry.  Fully legalize the coca leaf.  If people in drug consuming countries like the United States could freely purchase large supplies of coca leaf, they could refine it into cocaine themselves.  Cocaine and its manufacture could be kept illegal, but by allowing people to easily make cocaine without any outside help - there would no longer be a point to smuggling the stuff.  Not by boat or the in bellies of the poor.  
There would still be cocaine use and presumably problems with cocaine sales, but even this would be a serious improvement over the present situation.  Instead of an industry with top down distribution modes which inherently favor the establishment of powerful and intractable criminal organizations, drug warriors would face a drugs industry composed of small and localized "mom and pop" operations - far less threatening to society as whole.  
I can't say how realistic or attainable a goal legal bulk coca would be in the drug consuming countries.  But if we're going to press for drug reforms short of legalization, it's long past time we started talking about steps that would transform not only law enforcement but the drugs industry itself into a less malignant force.