In a sad way, it's been very successful in the context it was enacted: as a tool to oppress "minorities". It was never about actual dangers from cannabis itself.
"The Nixon campaign in 1968, and the Nixon White House after that, had two enemies: the antiwar left and black people. You understand what I’m saying? We knew we couldn’t make it illegal to be either against the war or black, but by getting the public to associate the hippies with marijuana and blacks with heroin, and then criminalizing both heavily, we could disrupt those communities. We could arrest their leaders, raid their homes, break up their meetings, and vilify them night after night on the evening news. Did we know we were lying about the drugs? Of course we did."
1994, talking to journalist Dan Baum, Legalize It All: How to win the war on drugs, Harper's Magazine, April 2016
Doctors either only did cannabis recommendations, or they didn't do them at all, so conventional doctors weren't bogged down by this.
As a doctor who sees patients with a legitimate use for compounds that come from the cannabis plant, the people who want recreational access just bog down the health system.
I am strongly in favor of federal recreational legalization, if for no other reason than to get it out of my office.
Prohibition has failed, and legalization is a far superior public policy option.
Recreational use should be available through places like Meadow, and medical use should come through conventional pharmaceutical manufacturing methods (like you would want for any other medication you take).