Why things fail arrogance of past success.
Too many of senior leaders across product and process built their success and career on x86. The success of the 90's and the past decade only re-enforced and entrenched those leaders to do the same thing.
They are the best, they know what the the customers want, they want the same thing as the past, build it and they will come because it is better.
How does a 50 billion dollar company that only has two things x86 and semiconductor excellence and a huge profit machine grow. Sorry Intel is no Apple with ability to redefine a new category of growth. The closest opportunity missed was Xscale and taking the Apple Apps processor but PSO blew that one. CRB had an idea but didn't execute it with communications. And BKs about 3Dnand, IOT, and all the fluffy around other things like drones, curie, charging bowl, fashion compute make about as much sense as past endeavors into microscopes and cheap cameras to to grow PCs.
Look back their are only two things this company had; 1 x86 high end compute, and 2 semiconductor manufacturing
x86 high end compute, it is clear when you look at Apple, ARM, Nvidia, or even Google Intel has no unique design expertise except the legacy x86 code compilation
Silicon, while revenues and technology are the best, the fact is they only know how to make one thing and one thing well. Factories are not set up to be flexible run very different things and frankly TSMC and Samsung now have smartphones that justify larger volumes at the leading node for iPhone and Galaxy lines that drive their execution. Intel execution has slipped as there is no competition and where there is none the entrenched get all full of themselves in telling others what is best. Frankly Apple and MS tolerate this but are now pursuing paths that let their success not be tied to whether 10nm comes or not and whether the 10nm product is revolutionary or a dud.
Then you got the leadership problem, no body in the current senior leadership has any track record of brilliance or leadership to speak of. Prediction is that this group will go down with the ship and be a classic Harvard Business Case study as well as the subject of a few books, like IBM was in the past.