The pot holiday '4/20' is a major sales boost for marijuana vendors similar to the way St. Patrick's Day lifts beer sales, said Christian Hageseth, founder of Green Man Cannabis and author of 'Big Weed.' Hageseth added that he tripled sales of marijuana this past weekend and won the 'Cannabis Cup' for the fourth year in a row. He said inefficient markets still make it possible for entrepreneurs to enter the marijuana business. In the long term, however, Hageseth said he expects big pharma and big tobacco to gain a huge share of the market, as well as a large consolidated company similar to the way Starbucks is the dominant coffee chain. Still, he said there will be room for small individual operators in the same vein as independent booksellers.