Interesting comparison... alcohol. Have you actually thought this one over though? Were are the Al Capones today... the ones running and gunning their way around?
Is there money to be made on things that are legal? Sure, so what? But this is really all about economics. About, again, the CONTROL of the Supply. Toyota makes a safer and better car than my neighbor Jim, who has illegal after market parts on his car drag machine in the garage with many missing safety features, and this not street legal. Toyota makes their cars better and sells them for less money too...
There are illegal rip-off products all over, but what impact do they make? Almost none... almost every person engages in legal buying and selling for almost all of their purchases.
What power would a Cartel have if they lost billions of dollars? Who would these guys employ as gaurds or chemists? All the best chemists would most likely work for a legit company where they would not have to worry about being killed or arrested.
Is pot going to be grown by some people around... sure. So what? It is still a fine or whatever, and there will still be some enforcement, as there is with boot-leggers, but is it even in the same ball park as a Cartel? Hell, is it even the same sport any longer?