It just goes to prove no one is irreplaceable; not even Jobs.
On one hand Tim Cook was able to pursue Jobs' job. That's refinement of initially very well designed and innovative products. Under the hood, I see annoying bugs that remain unfixed for years - is Cook able to motivate and manage his teams efficiently? Strategically, where is Apple going? An aggressive campaign to get rid of Chrome on the Mac that smells like the early days of Windows. The exceptionally good results of Apple are due to one thing: a bigger iPhone. Users have been wanting that for a long time, looking enviously at the giant Samsung phones for years. Now that everybody has a bigger iPhone, will they buy a new phone in Sept 2015? Unlikely.