The switch doesn't make sense to me. The ARM architecture can't really replace the X86 architecture or vice versa. I know Apple was able to design ARM chips that perform very well for mobile devices compared to some x86 mobile chips, but we are comparing the top notch highest end ARM chips with the low end scum of the X86 chips. When it comes to performance, X86 is unbeatable by a long margin, it doesn't matter if that's Intel or AMD. When it comes to battery life, ARM is much better.
Apple is trying to introduce the idea that the word "computer" is nonsense, all you need is an iPad pro. But that only holds true if you are a 10 year old kid with no real homework to do. I know that most people only use their computers for Facebook, email and very light task that could be done with some iPod touch, meaning that Apple has some incoherences to explain in their line up , why you keep selling laptops when all you need is an iPad with a "keyboard"?.
While the lowest end MacBook has a ARM like performance level with no so great battery life , at the very least the macOS Operating System deserves an appropriate CPU architecture, there's a hardware ecosystem and infrastructure around the x86 instruction set that make "computers" far more useful and pleasant to deal with.
For me, if true, this is a sign that Apple wants to abandon the desktop market. They make most of their money from mobile anyway.