The inevitable legalization of pot sets off a new California Gold Rush

Robert Gaither is a 39-year-old former salesman, a teddy bear of a guy with a full brown beard that makes him look a little like a mountain man. He does in fact live in the mountains — Lake Arrowhead, to be exact — but right now he is standing in an exhibit space at a downtown San Francisco hotel, showing off his wares at a conference exploring the intersection of cannabis, tech, media and finance.

Gaither is selling an expensive cannabis extraction system created by his wife, Brenna, a biochemist.

They…