The 2017 Handbook of Cannabis and Related Pathologies addressed the barriers that keep people from seeking treatment for cannabis dependence, and the researchers made a rather ironic conclusion. What is the most prominent reason why people don't seek treatment? Come on, you know this. Take a guess. You'd be right if you guessed it's because very few people think it's a problem or that they need any help.
More so than other prohibited or regulated substances, cannabis is not associated with a "perceived need for treatment." For those who think they need to decrease use, cannabis dependence involves "mild" withdrawal symptoms, and most people felt they could quit on their own. In other words, cannabis users felt it wasn't a big deal.
Interestingly, a secondary reason for rejecting treatment was the fear of negative attitudes and stigma associated with cannabis. This stigma stems from a century of misinformation that demonized the plant and its users, and it discourages the few people who think they need help from actually seeking it. So if you think more people should get help for cannabis dependence, you should know that prohibitionist propaganda is a major reason they don't.