I think you need to be careful to not draw too broad of a conclusion from these sorts of things. Look at the
Rat Park study, where they took morphine addicted rats and moved them from crappy little lab cages to a habitat where they could forage, hide, play, and make babies . Once in the new habitat the majority (67%) of the addicted rats
chose to get clean even though the drugs were made available. Even the rats that continued to use appeared to do so without addictive traits…