Can you imagine being the poor lawyer who has to defend a product liability lawsuit on Krokodil? "Well, yes Your Honor, my client's product did rot the plaintiff's flesh, cause gangrene, and premature death, but the plaintiff in this case was warned in advance..." Even conventional heroin has too much liability to make it defensible in court.
So drug producers and suppliers will still have to operate in a black market, so they can remain anonymous to their customers and thus free from liability. Legalization will change nothing.
Perhaps a warning label would solve that problem.
In the case of “krokodil”, I propose the following;
Caution. Use of this product may cause dependency, serious internal and neurological damage, catastrophic epidermal damage, and death. Use at your own risk: producer assumes no liability for damages or death which may occur.
Maybe accompanied by the photo of the young lady (?) whose arm looks like a chicken drumstick after a chihuahua got hold of it.
During the prohibition, people risked being blind from an inept stiller who produced methanol instead of ethanol.
With alcohol legalized, how many cases do you hear about people going blind from illegally run stills?
There will probably always be illegal drugs, but at least by regulating them we can ensure that minimum harm is done.
It would also free up resources to go after the worst of it, which should drive the costs of these drugs to unaffordable levels.