It would be relatively easy for the US to reduce the demand for illegal recreational drugs. But, it will never happen.
Drugs like heroin, cocaine, methamphetamine, and other dangerous and addictive drugs requires a considerable criminal infrastructure for manufacturing and distribution. Since these drugs are illegal, they are very profitable for the criminal enterprises that traffic in them. One of the things that these criminal enterprises must engage in to maintain their customer base is to use proactive sales agents (sometimes called "pushers") to recruit new customers. This recruiting often involves deception, and preying on the young and/or gullible.
The demand for addictive illegal drugs is, ultimately, created by those who seek addicts as their customers. Without this proactive marketing to create new drug addicts, the number of people who become addicted to illegal drugs would be seriously reduced.
If the high profits from the sale of illegal drugs were to disappear, then the criminal infrastructure needed to create them would soon disappear as well. If there was no market for cocaine, then farmers who grow coca plants would have to switch to other crops. The same goes for growers of opium poppies. With no production facilities turning the raw materials into finished product, and no smuggling networks bringing the finished product into the country, and no salesmen on street corners recruiting new customers, demand for illegal drugs would soon dry up.
Therefore, it seems to me that they best course of action to putting out of business the criminal organizations that are responsible for both creating the demand and providing the supplies is to undercut their prices enough to drive them from the marketplace. If the government were to use a carrot and stick approach, with the carrot being free supplies of sufficient drugs to eliminate all withdrawal symptoms and the stick being a much more aggressive campaign of arrest and incarceration for all addicts, I believe that the profits to the criminal enterprises who traffic in drugs could be reduced to the point where those organizations will be forced to find other business opportunities. That would take the retail-level dealers out of the picture, which would end the creation of new drug addicts.
I am totally confident that the approach I have described would work. I am also positive that it will never, ever be attempted.