Amazon sinks 10% after mixed 2Q results, lower North American segment margin and modestly weaker-than-expected advertising growth, but Wedbush analysts say they’d be buyers. The long-term thesis of the company is unchanged, they say. Amazon’s revenue mix is shifting toward higher-margin Amazon Web Services and advertising is structural and should contribute billions of dollars to incremental profit each year, the analysts say. That shift in business mix should combine with ongoing cost efficiencies in the core retail business to sustain operating margin expansion, they say.