Idk what part of "make society affordable for everyone and ensure that everyone has access to adequate care and social support" sounds like an easy or reductive fix.
Maybe my use of the world "simple" is causing some hangups. This is obviously a prerequisite for curing addiction worldwide. Lacking support, care, and social ties is a strong indicator that an addict will relapse in any case. You can't even start treating the really pathological cases without a comprehensive healthy environment for everyone.
The summation of the problem is reductive and your fix won’t fix it, although there’s no doubt it would help. No one is claiming your solution is bad, on the contrary it’s the best solution, but to claim it would completely eliminate addiction is preposterous.
Claiming the problem of addiction has zero nuance is one of the silliest takes I’ve ever read on here.