You can’t get high off rice, but people do eat lots of rice right, you might even call them addicted.
Cartels exist because they make large profits from trafficking in substance X. Now, if you can get substance X cheaper/simpler from elsewhere, then there will be no scope for smuggling/trafficking.
It’s irrelevant how many guns they have or how vicious they are. If there’s not a large profit to be made, they don’t really have a reason to exist.
Ever have rice wine? Perhaps not 'high' but it alters your mind as much as any other alcohol.