How do you measure success? If you were to ask this question to outgoing Apple CEO Tim Cook, he might answer with just one word — quietly. That is because Cook has made “quietly” a defining feature of Apple in the last 15 years. The company has grown quietly quarter after quarter since Cook took the reins in 2011. It has turned into a behemoth, this giant that crushes its revenue targets again and again. And unlike most other tech giants, which make noise on a daily basis in this way or that, Apple keeps doing it quietly. That is…