"The right environment" is key to your statement above. A slightly different environment, one that tolerates and is aware of the effects, both beneficial and ot

"The right environment" is key to your statement above. A slightly different environment, one that tolerates and is aware of the effects, both beneficial and otherwise, of stimulant and opioid use, would produce some number of people who's enjoyment of life, work productivity and effect on the world will be better when they abstain entirely - but others will have lives that are better when they consume some mind altering drugs some of the time. I imagine the number of people who become cripplingly addicted to a substance would be similar to the rate of severe alcoholics in society today. And we might decide as a society that this is an acceptable rate, and provide addiction care for those who are susceptible instead of forcing them to the margins of society.