It seems very unlikely to me that they'd switch the MacBook line to ARM and rely on an emulation layer to run current applications. ARM processors are getting faster all of time, but catching up to full Intel CPUs is going to be a very difficult task.
Meanwhile, Apple would have to support ARM-based MacBooks and Intel-based workstations until ARM became fast enough to replace workstation-level processors. While software makers caught up to the new architecture, MacBooks would lose much of their 'desktop replacement' status unless they truly could emulate x86 and x64 code with impressive speed.
I really doubt that Apple would split the architectures of their laptop and desktop lines.
Meanwhile, Apple would have to support ARM-based MacBooks and Intel-based workstations until ARM became fast enough to replace workstation-level processors. While software makers caught up to the new architecture, MacBooks would lose much of their 'desktop replacement' status unless they truly could emulate x86 and x64 code with impressive speed.
I really doubt that Apple would split the architectures of their laptop and desktop lines.