I’ve seen arguments that it largely comes down to the lack of a Jobs-like figure at the top maintaining a coherent, user-driven vision across the company and won’t hesitate to take a hatchet to projects and initiatives that aren’t furthering that vision.

Cook is excellent in terms of managing supply chains and has been good for the company’s bottom line, but he doesn’t have Jobs’ capability to discern what users want/need and what makes a good product, and I doubt he has anywhere near the level of direct involvement that Jobs had.

That’s not to glaze Jobs, he was anything but perfect but he was undoubtedly among the driving forces behind Apple’s quality and knack for building things that people want.