That's specious reasoning; consider that California had passed the compassion act in 1996, with the explicit intention of allowing this drug to be used for severe and chronic pain inlieu of harder narcotics (opioids). When the counties realized this was a cash cow, laws got relaxed and it was easier than ever to get high grade legally produced MJ, to the point where it was more accessible than alcohol or tobacco when I was growing up. The costs reflected that.
MJ legalization is and continues primarily be one of a money grab via taxes, in 2007 I went to CO on a school trip and I predicted that given the amount of illegal street deals MJ would have to be legalized at the recreational level, they were losing way too much tax revenue. In 2011 Amendment 64 was created, and in Nov of 2012 it was passed.
These trends and evidence is inline with basic projections of cause and effect from a local/state tax (or as its called in CO: revenue) matter and nothing less.
Japan did put lithium in their water in Aomori prefecture, and it had less than conclusive results on the general population to prevent suicide:
Anecdote: Colorado has experienced a population boom since 2012, not a reduction in population, so I don't see the correlation.
Greta Thunberg and Extinction Rebellion were here earlier this year in Denver, eco-centric protests have and will continue to be a thing so no one is being docile, if anything most are appreciating how we must protect Nature and stop things like fracking now where prior to legalization it went on unfettered and was a significant Industry in the state. Now potable water for Ag and residential development use is scarce and fracking is partly to blame.
Anecdote 2: California still suffered raids from the DEA up until as late as 2012; I launched my startup in fintech to service the Industrial Hemp Industry in part because I was on campus during 'Operation Sudden Fall' in 2008. It was terrifying to see a University get occupied by the armed goons of the State.
Also, weed is much stronger today than it was in the '70s and now you have regular folks walking around secretly addicted to pot . That was definitely not the case in the '70.