Interesting question. Am not too knowlegable on Apple and what people are already employed by the company that could take over from Cook. I think it all has to do with that. Finding the right person and get that person ready to take over. Perhaps Apple need a different kind of CEO now. Perhaps a bit more innovation again like Jobs was. Perhaps a combination between Jobs and Cook. I know the world of 'tomorrow' is going to be very challenging. AI is in its exponential curve up. The future of devices could very well be without a big screen, a keyboard and all that. Phone, Laptop, iPads may just be the devices of today, but in 5 years from now, not at all anymore. Apple need to be ready to adapt to stay relevant. You ask, Cook for the next 5 to 10 years. Well, 10 years from now the world is dramatically different. How it will look like, we can just speculate, but devices as we know them today will either be used totally different, or be replaced by devices we still need to invent, and/or commodotise (since most to all devices we can think of, are already on the market but didnt became a success for whatever reason). But, also totally new devices could be emerging coming half a decade to a decade from now. Cook shall either handle such transition well, with foresight and willingness to experiment and perhaps even drive the market (like Jobs did), or he shall hand over the CEO position to someone else who can do that.