http://www.slate.com/articles/news_and_politics/altered_state/2014/01/colorado_marijuana_legalization_how_lucrative_is_it_to_be_a_legal_weed_dealer.html
Your link doesn't say they’re purchasing illegally grown pot and selling it through legal retail shops. Here's what it does say:
"CT does not have to pay licensing fees, taxes, or other regulatory expenses. Over the past few years he’s dropped his rate for an eighth from around $50 to $30 to meet or beat the going price at Colorado dispensaries"
In other words: legal pot is cutting into illegal profit margins, and lightly taxed and regulated will do so even more.
Colorado Marijuana Legalization 2015: Fighting The Black Market And The Everyday Challenges Of Selling Legal Weed
BY DION RABOUIN ON 05/18/15 AT 3:22 PM
DENVER — It turns out selling weed is pretty hard. Contrary to popular belief, selling it legally, at least, isn’t all THC-infused lollipops and rainbows. Just ask David Schwartz.
The six-year cannabis-industry veteran came to Colorado in the ‘90s from Long Island, New York, after discovering Boulder on his way to a Rainbow gathering in Wyoming. For him, selling marijuana in a locale known around the nation for its liberalized pot laws is not just about counting money; it’s about taxes, regulatory compliance, inventory management, and above all, staying on the right side of Colorado’s “pot cops” — the Marijuana Enforcement Division (MED).
“Every single aspect of the industry requires a fair amount of consciousness and due diligence,” says Schwartz. “Your daily sales have to be loaded into MED at the end of the night, all your weights have to be accurate, you have to account for anything that dries up or goes missing. Every day you’ve got to do an accounting of what’s in your inventory.”
And then there’s another unique problem: the competing black market dealers who have none of the costs of operating a lawful business and often have access to product of similar quality. Marijuana advocates long suggested that legalization would be the key to wiping out the black market for marijuana, but almost a year and a half into the experiment, that hasn’t been the case.
About five miles from Herban, smoke is in the air and a dealer armed with three small baggies of Sour Diesel marijuana is doing business the old-fashioned way. The dealer spoke with International Business Times on condition of anonymity, in part to avoid possible arrest, but primarily because he fears backlash from people in the legal industry with whom he once worked.
He used to sell marijuana legally, he says. He owned a business that operated out of a modest building in Denver, but he grew disillusioned following what he saw as excessive regulation, uncertainty and taxation. College educated and previously struggling to keep up with the city’s rapidly rising rents, he says he now operates his marijuana business much the same way he did in high school: out of his car.
The state’s Amendment 64 ushered in a new era of business last year, allowing for marijuana to be sold for recreational as well as medicinal use. That brought a wave of new customers to pot dispensaries and a flood of cash, but it came with a cadre of regulations governing just about every aspect of who, what, when, where and how marijuana could be sold.
Skirting these regulations and free of overhead costs, sales tax and MED regulations, this dealer estimates he’s making two to three times as much money as when he owned his marijuana business.
And his clandestine delivery service is just a tiny part of the equation in the state’s black market.