Yeah, the Pusher-Man needs drugs to remain illegal to keep his pockets full. Unfortunately, the enforcement community also hates the idea of legalization, at least at higher levels, for a number of reasons. Most of them also having to do with money. Think of all the pot busts they make. It's like shooting fish in a barrel. It's their reason for being. It's their justification. It's how they keep the money flowing into their budgets. Pot prohibition makes it Easy Money. They've shown their resolve in this matter time and time again. They don't give a shit even about medical use. They'd rather see cancer and aids patients die of malnutrition than make weed available to those it can help. I believe it also gives them a reason to keep their finger up the ass of what they have long regarded as a subversive element of society.
Legalize weed and you cut yearly busts by half. Not to mention the decline in crime due to the other crime that revolves around the drug trade. Pretty soon they're going to have to cut budgets and jobs. No bureaucrat worth his salt wants that. Even if it's the right thing for the people and the country. It's simple self-preservation. They can't let it happen. Cops need illegal drugs just like God needs the Devil. Do you think that the DEA heads are going to let their cushy jobs just evaporate just because a bunch of pot heads want to smoke their herb?! Fuck that, they'd say. It just doesn't serve their purpose.
Let's not even talk about all the industries that support drug enforcement. You're talking about billions of dollars. Prisons are a booming industry. Prohibition keeps them overcrowded, with people demanding more and more facilities. Do you think that the companies that build, maintain and manage prisons have any reason to see pot legalized. Fuck no. They'll lobby against it. The pharmaceutical industry is annother issue. Weed is a medicine cabinet on a stalk. Trust me, they are afraid of pot, and will do what they have to in order to keep it as a schedule one drug. They're incredibly powerful. The list of wealthy, powerful industries which have a vested interest in maintaining the status quo is longer than your arm.
Then there's even darker reasons. It's been pretty well doccumented that our government and others often support groups involved in the manufacture and distribution of illicit drugs, in return for intelligence, and manpower, in reigons where they have no other way to get a foothold. Once they begin legalizing drugs it becomes harder to hand out drug monopolies to the people they want to work with. Prohibition works for agencies like the CIA. Listen to this NPR interview for more about the CIA and drugs:
Worldview - Geopolitics of Drugs: The Politics of Heroin
This thing is way more fucked up than most people imagine.