Their margins tend to allow them to always use the latest TSMC process so they will often be pretty good just based on that. They are also ARM chips which obviously have been more focused on efficiency historically.
They actually work with TSMC to develop the latest nodes. They also fund the bulk of the development. It's not as if without Apple's funds someone else will get the same leading edge node.
Oh how the mighty have fallen. For decades, when comparing Mac versus PCs, it was always about performance, with any other consideration always derided.
Yet here we are, with the excuses of margins and silicon processes generations. But you haven't answered the question. Is Apple pulling ahead or is the x86 cabal able to keep up?