[DiogenesLamp]

While in a “park” setting with activities, good food and friends the rats chose sobriety on their own. Even going as far as overcoming their chemical addictions without help.

You mean a park like this?

Doesn't seem to confirm your theory, does it?

[varyouga]

“Park” refers to overall change in environment. For humans that would include change to nearly every aspect of modern society. Not just giving destitute people a piece of concrete to use drugs.

This is a view of what happens when you place the drugs at one corner of the cage. Of course rats who are sick and in pain from the cage will gather and die at the corner where they find relief.