I lived through both major Mac CPU transitions (68K-PPC and PPC->X86) and in both cases the assumption was that it was impossible for Apple to ship a usable emu

I lived through both major Mac CPU transitions (68K-PPC and PPC->X86) and in both cases the assumption was that it was impossible for Apple to ship a usable emulator. In both cases Apple proved everyone wrong and in fact the emulator was a major contributing factor to a smooth transition. It simply takes a lot of time for all 3rd party software to be released for the new architecture. Given how they handled it in the past my guess is that Apple will release a very usable X64 emulator for the ARM and really brag about it at WWDC.