Jem Aswad Senior Music Editor When YouTube chief business officer Robert Kyncl announced late last month that he’ll be leaving the company after 12 years in the job, many observers quickly moved him to the front of the line to replace outgoing Warner Music CEO Steve Cooper, who’d announced just two months earlier that he’ll be stepping down after 11 years in the job. After all, Kyncl knows the music industry — YouTube is both the world’s largest video-streaming platform and the largest music-streaming platform, and he played a huge role in its negotiations with labels and publishers and generally received high marks (remarkably, considering the often-contentious relations between the two sides). He’s also pioneering force in the streaming business: Before he was chief business officer of YouTube, he led Netflix from DVDs to digital, a transition that was much more complex and fraught with potential failure than he and the company made it seem.