The thing is, they already are. Excessive drinking at a friends house is so normalized here, it's become background. The police might pull you over if you're swerving all over the road on the way back home, but usually they wont. Adding weed to that mix of "normal" background behaviours is going to improve that? I don't think so.

And I'm not saying prohibit all vices. People need their release - of course they do - but rather than encourage new addictions behind closed doors, can't we just make it easier for people to hang out in public at night?