CPU changes. Once when MacOS went from PPC to Intel, and then once when MacOS went from 32 bit to 64 bit. Each time that transition happened Apple was able to say “OK, this legacy stuff just isn’t going to be there on the new architecture”. And since you had to recompile apps anyway to make them run on the new architecture, developers kind of shrugged and said “Well, yea. That’s what I would have done too”. It made sense.
So are we about to see 128 bit Intel processors anytime soon, to facilitate this change? I doubt it.
OK then, what about a new architecture?
Oh. Hello 64 bit ARM.