That article puts the real issue front and centre: the Dutch have effectively decriminalised minor drugs but haven't taken the essential step of legalising supply and distribution. That's what needs to happen to prevent the criminal gangs from profiteering.
When we were walking round Amsterdam it was surprising just how difficult it was to find cakes with cannabis, for example. To some extent, they're still almost underground. My argument's long been two pronged: criminalising the people who take drugs doesn't work. Never has, either, but what it does do is encourage illicit supply.
The second prong is simply that because we know - conclusively - that criminalising drug users and suppliers has no effect at all, and because it's patently absurd that any supermarket is free to sell psychoactive and dangerous drugs on its shelves in the form of alcohol, then we need to grow up as a society and legalise supply and demand of all drugs, then add tax, before making their sale subject to the same restrictions imposed on sales of alcohol. The treasury benefits, which means we as taxpayers benefit and illicit drugs are controlled far more than they are at present.