When marijuana is legal nationwide, it will not stand alone without affecting other industries. Of course the jobs created will lead to economic activity across the board as these employees spend their paychecks. But more specifically, the cannabis industry itself will directly benefit several industries.
Of course tourism will benefit greatly from legalization, especially in the initial states that legalize; they have the advantage of the novelty of legal cannabis to draw people in. The banking industry can benefit immensely as well, assuming the federal government ever allows them to. After all, all of that money has to be kept somewhere secure.
A more surprising industry that will feel the effects of marijuana legalization is the staffing agencies industry. As states legalize, new businesses will have many open spots to fill; staffing agencies could be used to fill that void with workers who are ready to go.
The security industry also stands to benefit as new owners look for ways to secure their businesses and products. The same is true of the gardening industry as thousands upon thousands of new legal growers purchase the supplies they need to start cultivating top quality cannabis.
Just to be fair, it’s also true that some industries will suffer. The private prison industry will take a hit as they lose some of their slave labor. The pharmaceutical industry stands to take some big losses as more and more people stop using their deadly and addictive pills and find out about the healing power of cannabis. And the civil forfeiture business law enforcement engages in will be decimated.
But for the most part, the US economy stands to gain a lot by bringing a massive black market industry into the realm of the legal marketplace. As mentioned, the jobs created alone will serve as a major boost to an economy that has struggled for many years now.