The reason to take those substance is to get a modified state of mind. In that effect, they are successful. It's not comparable to something that was just doing 'nothing' toward its stated goal. The goal is not to live to 120+ years. No one takes coffee thinking 'this will help me live an exceedingly long life'.
On the other hand, it's not so much imagining a society with this list banned that is difficult. It's to imagine a government capable of enforcing such banning.
I think it is infinitely more likely that in 50 years, it will be recognized as a folly to have spent so much money into trying to ban those substance. If the goal is to effectively reduce consumption, outright banning is not the way to go. Also, I have a personal belief that mental health is on the verge of revolution, and psilocybin in particular will be made more available, possibly even for recreational use.
I have not seen a good reason for now to reduce my caffeine consumption. I drink two cups per days, one of which is decaffeinated. I try to read regularly to see if new info arises there, and so far nothing. The only justification I might have to stop this consumption is the work condition for the producers and having to import it from afar.