Fun fact, in the late 90's, Intel was the biggest manufacturer of ARM chips. I was there at the time, and I wrote lots of software to aid in their design.
What happened to Intel was twofold: The first problem was that Robert Noyce, Andy Grove, And Gordon Moore died. Each one was a once-in-century intellect, and it took Intel a while to be able to find somebody who could remotely fill those shoes.
The second problem was Intel was making so much money on x86 chips, that dedicating any fab capacity to anything else--including chips for Apple's iPhone, would for years have had such a huge opportunity cost, that the shareholders would have sued, and with cause. Because literally (not metaphorically) anything they would have manufactured instead would have had a drastically lower profit margin, and the stock would have tanked.
I suspect that the only reason Intel made a foray into ARM chips in the first place was to head off anti-trust accusations, and once the political heat was off, they dropped them like they were hot.
By the time the market shifted, almost a generation of mediocre management had left Intel less paranoid, and therefore, less likely to survive.