My opinion,
Apple doesn't want to shake the boat too hard and get the kind of repercussions that Microsoft is currently getting, or those that Nokia and RIM already took for "alienating the userbase"
Let's take a closer look at what the "other phones/devices" did
Nokia: All but completely abandoned Symbian, a perfectly fine OS, for what? Windows Phone
RIM: Delayed BBX, released half-baked tablet
Microsoft: Released Windows RT, Windows Phone, and few people bought. Their previous Windows Mobile platform was perfectly fine up till iOS came and sunk their ship.
iOS is rapidly replacing Nokia, RIM and Microsoft as the choice device for End users, Enterprise, and even as school tools. No Android device is doing this at all.
Android is replacing the lower-end devices, those that were primarily Nokia, HTC, Motorola, Samsung, LG, and all the other chinese throw-away phones. Overall this is a good thing, because users get used to "smartphones" and may switch to iOS if they really find having applications or the internet on their phone useful. But really... Android is for the soccer moms to check their facebook. Nobody who wants to make money will ever make their software exclusively for Android, those that do make Android ports, will just make it work on the Samsung device, and to hell with all the other devices.
In another 5 years time, the market will likely be only Apple (30%) and Samsung(60%) for mobile devices, assuming neither company makes a foolish mistake that results in platform abandonment. Samsung isn't shy about making disposable devices, where as Apple's devices last as long as the battery will. The average Apple device can be used for 7 years. This is not yet true of any Samsung device. Those I know who have Samsung or LG devices barely get 11 months out of the device.
On the Desktop and Laptop side, Apple has never been "the market leader" yet they are still growing Year over Year, at the expense of Dell. Go watch any television show on TV in the US. You will see Apple laptops, iMacs, and iPhones/iPads. These computing devices are fashion accessories, not just useful tools.
But I think Apple needs to come back to earth and focus on their core businesses (software) and the hardware that people buy. The Mac Pro was last updated? More like, hasn't been significantly updated since 2009. That is TOO LONG to go without a refresh. Likewise with the iMac, the last refresh before the current one was 3 years before.
If Apple continues down this road of not updating the desktops, they're not going to have any customers for which to buy the professional software either, and everyone will be forced to switch (back) to windows systems. But Windows 8 is flopping. So users will probably decide to dump their desktop/laptops entirely if it's possible, hence the iPad or some other future tablet device may replace all the entry-level desktops and laptops.
