I don't really think entropy is relevant to the war on drugs...
Well, it is, but not at the scales we care about.
Does entropy last forever?
Marijuana is legalized for recreational use in two states, and for medical use in twenty-three (including those two recreational states). It's also decriminalized in six more. The national government is starting to talk about rescheduling it as well.
There'll still be other drugs to chase after but clearly SOMETHING is changing here.
It's fully legalized here in Uruguay, and the sky hasn't fallen yet.
General optimism, hoping that certain culture wars (the 60s) will age out generationally, some positive evidence from countries with harm reduction focuses (Portugal).