correct …Its evidentially 5-6x right now all things considered."3-4x"? It's nowhere near that even now with AMD's and Intel's node disadvantage.
It's not Apple that achieves process improvements, it's TSMC. At the moment Apple happen to be the first to use TSMC's 5nm process for a computer CPU, but that won't last.
Yes, its probably going to last for the next couple of years. Apple purchases exclusive as it seems. Once Intel/AMD are on 5nm, Apple is on the next gen node, very likely exclusively for quite a while