Or maybe we, because its not illegal, have just learned how to deal with drunkards.

Yep. There is virtually no difference between (the physiological effects of) THEDEVIL'SWEED and alcohol except nobody has ever died from an overdose of THEDEVIL'SWEED. LINK

But in a real society you would never let someone get lost in the depths of drug addiction.

Well, you can only really "expect" people to care about their own friends and family members.

You would work at healing the underlying problems that lead them to want to check out.

Or I would hope, at the very least, give them some humane option to "cancel their subscription" so to speak.

Probably the best course of action is, "you grow your own food", if you do not grow your food well enough or in enough quantity because you are too drugged up, then you die.

Or become a beggar? Aren't beggars integral to a "real" society?

Also growing your own food really grounds a person. Being in touch with the land actually heals a lot of the woes of people in the city.

I agree, but it really should be "voluntary".