Obviously that was built upon years of iPhone experience, but it shows they can lag behind, buy from other vendors, and still win when it becomes worth it to them.
They could change the architecture again tonight, and start releasing new machines with it. The users will adopt because there is literally no other choice.
Every machine they release will be fastest and most capable on the platform, because there is no other option
You can also voluntarily cut off huge chunks of your own app ecosystem intentionally, by giving up 32bit support and requiring everything to be 64bit capable.
...because users have no other choice when only one vendor controls the both the hardware+software. They can either use the apps still available to them, or they can leave. And the cost of leaving for users is a lot higher.
Microsoft and Qualcomm already knew the performance of x86 app emulation on windows was killing the ARM machine lineup, so Qualcomm was working on extensions to their chips and Microsoft on having Windows support them already, but ARM64EC and Prism didn't launch for two years after the M1 shipped.
I had the initial m1 air, and it was remarkable how useable it was. You'd expect all sorts of friction and issue but mostly things just worked (very fast). Even with some Rosetta overhead it was still fast compared to intel macs.