I wonder if intel is betting on increased centralized cloud computing as the way forward for personal computers. So the efficiency benefits of ARM are irrelevant in their minds since they think the real power will come from big data centers.
AWS has a shitton of in-house "Graviton" ARM stuff available and the ARM server chips from Ampere are popping up in more and more places as well. Most Linux servery distros have ARM images available now, and most software builds without major changes. It's a slow transition but it's already happening.