I still wonder if Apple will try to really get to Intel levels. It's unlikely their micro-architecture can reach as high frequencies as Intel, so they'd have to sacrifice IPC. But nonetheless their current chips are incredibly efficient.
Why are you so sure about this assumption?
Let me try challenge it.
Apple's CPU's are around 2 - 3 GHz which are around the numbers of Intel 2xxx generation.
Transistors wise, they have similar number of transistors (Remember to remove the GPU from both chips when doing the calculation) and since Intel's CPU has larger TDP Budget it means Apple's better manufacturing is meaningless.
Yet Apple have better IPC.
Intel, from that point, increased their speed by 30-40% and improved its IPC.
Namely, there is no physical law which will enforce Apple to reduce its IPC in order to increase speed.
Apple curve is better than Intel's curve on the most important measure, given a budget of Transistors, which one extracts better performance?
I would gamble that in the years to come Apple will both increase its speed and its IPC.
That's what history tells us, Intel did it, no reason Apple won't...