Drew Houston, chief executive officer and co-founder of Dropbox Inc., smiles during The Wall Street Journal Tech Live conference in Laguna Beach, California, U.S., on Tuesday, Oct. 22, 2019.Martina Albertazzi | Bloomberg | Getty ImagesDrew Houston founded Dropbox nearly two decades ago out at age 24, eventually becoming a household name in Silicon Valley and the first tech entrepreneur to take a company from the Y Combinator incubator program all the way to the public market. Now, at 43, Houston...