Apple are good at architecture migrations. They have successfully pulled it off several times. For App Store apps, Apple can easily add fat binary support for

Apple are good at architecture migrations. They have successfully pulled it off several times. For App Store apps, Apple can easily add fat binary support for apps with ARM and x86 code in the same package. They control Xcode and can force resubmission of apps for a future version of MacOS. The thing is, they need to be able to efficiently emulate x86 at current performance levels for regular software while those developers migrate to the new architecture. This might require new ARM instructions or changes to the graphics processors to assist with performance issues. The end result is that they need to give their hardware and software folk time and allow developers enough time to get their applications ready. I'm guessing 12+ months from when the new tools become available. Unless they have been working on it for a while, this suggests 2020 models might be capable. I would also like to speculate that if they add a fabric interconnect to A13/A14 chips, they could have several sockets in each product resulting in massive performance for the high-end pro models with a very flexible power and thermal budget.