Despite billions spent by the enforcement industry,people still smoke weed. The only possible reason for it to be illegal is that a lot of people have vested interests. Police are worried about their budgets being cut and private prisons would be only occupied by actual criminals. It is so hypocritical for a society awash in gambling and booze to persecute folks for indulging in a mild vice. If it were taxed and regulated like booze,society would only benefit.
I've never known Pot to be the only drug that people get hooked on or commit crimes to feed the drug habit. Actually, I've never heard of Pot-heads to be convicted of muggings or brutal in home invasions to "feed their drug habit" Mostly, pot heads "get creative" and build all kinds of stupid s***.
Usually, if they "plan to do something" they usually end up forgetting what it was they started out to do.
Out of all the drugs, Pot seems to be the less dangerous but by no means is it harmless. It does kill brain cells with long term use.....yes, I know, alcohol and cigs are not beneficial to ones health either, and prolonged or extensive use/abuse of either can be harmful in many ways.
As you stated, there is so much money invested in police operations regarding Pot, but I would think there is much more involved in operations having to do with coke, ice, smack and all the other hard-core drugs. THE MAN doesn't want to lose "control" of any sort it seems