When Terry Kawaja, founder of investment bank Luma Partners, stood on stage at the Association of National Advertisers’ annual Masters of Marketing conference last year and told a packed crowd that they should fire their CMOs, a challenge was set. Kawaja encouraged established giants such as Unilever and Procter & Gamble Co. to either adopt more direct-to-consumer strategies, or risk losing their lunch to the growing field of buzzy startups like Harry’s and Everlane.