To put things very bluntly and succinctly, I think Apple may very well catch Intel off guard with respect to desktop performance with ARM.
Take Apple's Cyclone CPU core or one its successors and put it an form factor that is not thermally constrained (eg, Apple TV and make it it more like a Mac Mini), boost clocks and we could have whole wave of desktop like Apps we are not used to seeing in the ARM ecosystem follow soon afterward.
Therefore, I believe Intel needs to approach and think about value desktop in a way they have never thought about before.
Once ARM catches Intel off guard, it will be very difficult for Intel to regain what they lost IMO (maybe a good example of this is the phone SOCs). Instead, I would like to see Intel take some kind of pro-active and aggressive stance now than have to react defensively later on.
P.S. Also at some point, I think Intel needs to plan on offering eMMC 5.0/UFS 2.0 or one its successors as an option for their big core APUs. This way the cheapest class of big core motherboards can have a BOM lowering form of primary storage if necessary