Assuming the Apple-designed ARM chip is indeed significantly more performant than the x86-64 chip (there wouldn't be much point to this transition otherwise --

Assuming the Apple-designed ARM chip is indeed significantly more performant than the x86-64 chip (there wouldn't be much point to this transition otherwise -- if it was solely about business concerns with Intel, they could use AMD's x86-64 chips instead), they could do an emulation mode of some kind. They could potentially even have some hardware optimizations for it. Apps like photoshop would still get compiled targeting the new architecture to take advantage of the performance benefits, but other apps could run in emulation mode. Then, over say 3-4 years, most commercial and open-source apps would get updated or be replaced by alternatives. On one hand, it's weird to use a different CPU than other computers. On the other hand I hate x86 and its complexity and its weird hacks, and it's about time someone ditched it. Although they literally just actually completed the transition to x86-64 a few months ago so it's a bit hilarious they're moving away so soon.