Intel’s problems started with Itanium.

Sure, the Core 2 series ultimately, after a long gap, put them back on the rails at least, but Intel missed big iron and panicked.

Everything else since has been about desperately squeezing x86 into every niche, even when it probably shouldn’t be. That the Core 2 series gained an Apple-shaped halo is lucky for them, but the reality is that they have been on the back foot at some level since the failure of IA-64.

They needed to get themselves out of the hole by using AMD’s architecture, and they have been a polar bear on a large but shrinking iceberg ever since.