The most likely cause of Intel's lagging is a wall of cost/benefit to being both designer and fab. This hit AMD earlier by being smaller(and arguably, with a different management style, AMD could have held on to their fabs longer) but each node only gets more expensive and harder to keep busy with orders which in turn means a greater need for external customers to fund R&D.
Intel had a reprieve of almost a decade with a weak AMD that let them coast along with the desktop monopoly and extract a yawn-worthy 5-10% improvement per generation, but now that they have the incentive to compete again they're struggling to get their house in order - the chip design hasn't had a major refresh in a long time and they have been very late with their version of 10nm.
So they're really at a crossroads now where they can't rely on old tactics and their long-term prospects are in serious doubt, since they didn't position themselves to counter the efficient small-core/big-package architecture that AMD is pushing with the Zen chips. For now, they can still put out competitive flagship product launches simply by binning extremely expensive parts and running them hot(e.g. compare i9 and Threadripper) but that advantage might erode within one more generation.
Intel had a reprieve of almost a decade with a weak AMD that let them coast along with the desktop monopoly and extract a yawn-worthy 5-10% improvement per generation, but now that they have the incentive to compete again they're struggling to get their house in order - the chip design hasn't had a major refresh in a long time and they have been very late with their version of 10nm.
So they're really at a crossroads now where they can't rely on old tactics and their long-term prospects are in serious doubt, since they didn't position themselves to counter the efficient small-core/big-package architecture that AMD is pushing with the Zen chips. For now, they can still put out competitive flagship product launches simply by binning extremely expensive parts and running them hot(e.g. compare i9 and Threadripper) but that advantage might erode within one more generation.