Not everything SJ touched turned to gold. Remember the fiasco when the original iPhone was released? Apple dropped the price only weeks afterward. That seemed desperate at the time. Now the iPhone business alone is bigger than Microsoft.
Every CEO, including SJ, has to be accountable to the board. It's really too early to judge Cook on the moves of this week.
This is an important point. People tend to have short and selective memories. I attended MWSF as media every year from the late '90s through the mid-2000s. I got to see a lot of keynotes, and let me tell you, not every one of them was anything close to blockbuster. After some of them, we walked out looking at each other asking "so, that's it?" In fact during one keynote in particular I remember Steve sounding distinctly peeved that he had so little new to tell us. Even people who should know all of this seem to have forgotten that Steve's time as CEO wasn't an endless stream of success and innovation.