Apple couldn't just go for ARM they'd have to adapt their OS for that and I assume by now there is a lot of code in there making use of x86 quirks not easily ad

Apple couldn't just go for ARM they'd have to adapt their OS for that and I assume by now there is a lot of code in there making use of x86 quirks not easily adaptable to ARM I don't think the OS is the problem. First, macOS went through PowerPC -> x86 -> x86_64. Secondly, iOS and macOS share a lot of components, including the kernel. More difficult would be moving the app ecosystem. Apple could do PowerPC emulation with Rosetta, because Intel CPUs had leapfrogged PowerPC by quite a wide margin at that point. It's probably a more difficult feat to put off with x86_64 -> ARM. Though, I think Windows ARM (at least) does x86 emulation. That said, Apple has a lot of leverage with/over the ecosystem. Most macOS/iOS developers are already used to having to fix their applications for the next macOS/iOS iteration, so Apple probably won't have much trouble convincing developers to add ARM as a target. However, if this happens, we'll probably have fat binaries for some years again. For backwards compatibility, but it's also likely that they are not at the point where they could replace the Mac Pro yet. It would be smart for them to do the transition though. They would not be dependent on Intel's cycles and product decisions anymore.