The legal cannabis industry, currently worth about $8 billion, is predicted to triple in size to $22.6 billion in total annual sales by 2021, and it's catching the attention of powerful leaders around the world. In 2015, Alan Gertner left his role as head of Google's Asia-Pacific sales team in Singapore to run a high-end cannabis brand, Tokyo Smoke. Former House Speaker John Boehner recently joined the board of directors of a cannabis-focused holdings company. Stormy Simon, the former president of Overstock.com, is among those betting big on bud. When she decided to leave e-commerce in order to take on the cannabis industry, Simon's friends told her it was "career suicide." But she predicts the cannabis industry is going to be just as big.

"To come from the professional background that I have, to walk away from an amazing job at a company that I absolutely played a huge piece in building — you have to have a passion," she says. "My passion came from the research I have done, and from watching Colorado and their economic benefits. This just makes sense across the board."

Overstock.com warehouse Ken James/Bloomberg | Getty Images

This is not the first time Simon has rung the alarm about a major industry trend. In 2001, she took a job at Overstock and was inspired by the potential growth of e-commerce. "I walked in the door looking for something for a couple of months and wound up being completely inspired by the shift that retail was undergoing," she tells CNBC Make It. "I joined in 2001, and early on there were no e-commerce experts." After working for Overstock for over nearly 15 years, Simon became an e-commerce expert herself, helping build one of the largest online retailers in the world. Now, she is quickly becoming a cannabis expert. Simon is on the advisory board of KIND financial, which develops business and technology solutions for players in the cannabis industry. She's also on the advisory board of CannaKids, an organization that advocates for safe medical uses of cannabis for sick children, as well as the board of directors of publisher High Times. Her decision to invest her time in organizations across the industry was originally inspired by a personal belief that access to legal marijuana is a civil right. "Cannabis has helped me with my own ailments," she says. But she also emphasizes that the industry is also going to make people rich. Entrepreneurialism and cost-efficiency, she says, are going to allow cannabis to disrupt the healthcare sector the same way that e-commerce disrupted traditional retail.