What makes you think they'll have to? Lots of criminal enterprises have 'legitimate business' operations too.
Just like the mafia. I guess you have to launer your money somehow. And just like the mafia, or the teamsters for that matter; you don’t deal on their turf without them getting a piece of the action. Legalizing pot is one thing, but this isn’t like prohibition. Prohibition was short-lived, the drug cartels have had decades to build up empires, and like all empires they’ll fight to maintain control. If you want pot, I don’t care, I’m just pointing out what I’ve seen happen in the past.