If you look at it from a commercial point of view, pot could be marketed sold and taxed just like alcohol or cigarettes. Harder drugs simply could not as they are widely known as dangerous and harmful substances making them at the onset defective products.
No producer could ever get the financial backing or insurance coverage necessary to bring these products to market. The product liability would be astronomical.
So the drug war would continue with the manufacture and smuggling of everything from cocaine to zanax to heroin to X.