According to the website Marijuana Business Daily, cannabis-related companies are already employing more than 100,000 workers, including up to 27,000 involved in cultivation, 52,000 in dispensaries and 66,000 in ancillary industries.
Even some Britons have got involved in the green gold rush especially in the "Emerald Triangle", the region north of San Francisco, where much of American cannabis is grown.
Known as "trimmigrants", their expertise is in snipping the plant leaves to expose the highly valued buds rich in cannabis resin.
The sales figures have been pretty staggering. Colorado, the first state to legalise recreational pot, is estimated to have generated more than US$1bn in retail sales last year.
According to the latest projections, sales in California, Nevada, Maine and Massachusetts - states which legalised the adult use of marijuana in November - could top US$6.5bn a year.
"Some analysts believe that by 2021 recreational and medical marijuana sales could hit US$35bn in the US. That's as big as the wine industry," says Frank Lane, president of CFN Media, a company promoting and analysing the cannabis sector.
In Canada, estimates vary. David Brown, the editor of Lift News, which specialises in the industry, believes that recreational pot sales are on course to be worth as much as US$6.5bn a year.
Other analysts are even more bullish. Russell Stanley of Echelon Wealth Partners has predicted annual sales of more than $8bn a year by the end of the decade.
Given these figures, the interest in earning money from cannabis among cash-strapped politicians is hardly surprising, especially in the United States where they face the prospect of a drastic cut in federal support.
Colorado, for example, raised US$67.1m in sales tax last year.
"We have looked at states like Colorado and that is what we are basing our calculations on," says Kelly Cassidy, a member of the Illinois state legislature and a sponsor of the marijuana legalisation bill. Colorado set the legal and commercial template for the rest of the country.
"The market divided into four segments," explains Professor John Quelch, of Harvard Business School and Harvard School of Public Health.
"There is legal medicinal use where it is available on prescription, the recreational market, the homegrown market, which in turn spills into the illegal, unregulated, untaxed and unsupervised street market."
Of course street cannabis, which is untaxed, is cheaper. In a detailed analysis of the Colorado market, he found that recreational consumers divided into two distinct groups.
"There is still the long-term pothead from the Woodstock generation who is still puffing away and first time users, many of whom are women, who don't want to be seen smoking a joint, but do want to enjoy the high of consuming marijuana.
"For them, the edible and drinkable products tend to be more palatable."
It is less than three years since Colorado legalised recreational cannabis. In almost the blink of an eye, the political, commercial and industrial landscape surrounding pot has changed beyond recognition.
Marijuana moguls abound. Derek Petersen, a former Wall Street banker, is among the best-known. He heads Terra Tech, the first publicly listed company to "cross the green line" and make products from cannabis. His involvement in the industry was triggered by a surfing accident in which he broke his neck. Unable to cope with Dilaudid, the opiate prescribed by his doctors, he turned to cannabis.
Petersen was among the first to join what has become known as the "weed gold rush", setting up a company to sell equipment to cannabis growers who were supplying the medical marijuana industry. It was a move which led to his being sacked by Morgan Stanley in late 2010.
Terra Tech went public in 2012, two years before recreational pot was legalised in Colorado. As more states fell into line, the company evolved from growing pot to selling the product in dispensaries in California and Nevada.
The company has grown dramatically. Two years ago it employed around 20 people, now it has around 200. It expects to have earned between US$20m to US$22m in revenue last year.
"I think the industry will continue to grow," Petersen says. "I expect it will bifurcate between medical and adult use.
"The medical side will become heavily biotech, working with the Food and Drug Administration, while adult use will become much more about lifestyle and branding."
When it comes to branding, it would be hard to top the deal reached by Privateer Holdings, the world's first private-equity firm to invest exclusively in legal cannabis, with the family of the late Bob Marley.
Marley Natural cannabis is already sold in California and Oregon and, as legalisation spreads, it is expected to be sold in other states as well.
Earlier this month Brendan Kennedy, the Seattle-based company's chief executive, announced he had raised US$122m to invest in marijuana businesses.
Recreational pot is just one part of the company's portfolio. Its holdings include Leafly, which bills itself as the world's largest cannabis information resource, and Tilray, a federally licensed Canadian medical cannabis producer.
A graduate of University of California, Berkeley with an MBA from the Yale School of management, Kennedy could hardly be more blue chip.
At the other end of the entrepreneur spectrum is Snoop Dogg, the rapper whose street credibility more than compensates for any lack of establishment respectability.
An icon of the weed world for decades, he has not only put his name to the industry but has become a major investor, launching a digital media business called Merry Jane devoted to cannabis. "Merry Jane is cannabis 2.0," Snoop Dogg said in a promotional video two years ago. "It is a crossroads of pot culture, business, politics, health."
However, it is Tripp Keber who in many ways epitomises the inexorable march of the cannabis industry towards respectability. Keber started his business, Dixie Elixirs, in Denver, Colorado in 2009 during the early days of the "green rush".
He decided the industry had to move away from the days of smoking a rolled up joint against a musical backdrop of an interminable Grateful Dead soundtrack.
Keber realised the best way to sell cannabis once it became legal was as something which could be eaten or drunk.
It also had to taste pleasant.
"I know my 16-year-old daughter would rather ingest cherry-flavoured cough syrup than something which tastes really unpleasant," he says.
"Infusing cannabis drinks with flavours like cherry or rootbeer makes them extremely palatable.
His company's array of products includes an assortment of cannabis-infused consumables including berry lemonade and fruit punch elixirs.
There is also chocolate - milk, dark, peppermint and white - as well as a range of awakening and relaxing mints.
As the legalisation of marijuana continues its relentless progress, the industry has begun to develop the foibles of more mature consumer markets.
The discerning cannabis user can now look forward to enjoying a product appropriate to their needs and wallet. If ordinary marijuana is not good enough, there is the more expensive organic alternative.
Then there are the accessories. For a mere US$900 those who still wish to smoke cannabis can buy an exquisitely designed glass coil. Traditionalists can still enjoy a joint, but for US$55 for a pack of 12 sheets, they can roll it in 24 carat paper.
