Maybe, but the fact remains that they spent years trying to make an Atom that could fit the performance/watt that smartphone makers needed to be competitive, and they couldn't do it, which pretty strongly suggests it's fundamentally difficult. Even if they now try to sour-grapes that they just weren't really trying, I don't believe them.
ARM is typically [...] more efficient at idle.
From Intel's perspective, the decision to invest in x86 was purely fiscal. With the benefit of hindsight, it's also pretty obvious that licensing ARM would not have saved the company. Intel was still hamstrung by DUV fabs. It made no sense to abandon their high-margin datacenter market to chase low-margin SOCs.