While it's true that organized crime grew up during the bootlegging era, organized crime was on the upswing in the 1960's and 1970's, at a time long after prohibition had ended and before the modern drug war had started. Clearly, the fuel to feed organized crime existed without prohibition. Given that fact, it's hard to say that those organizations wouldn't have grown bigger and more sophisticated during that period anyway (just like corporations did, for reasons that had nothing to do with prohibition).