Yes, Katherine, the latest updates are powerful. Do you think Apple will keep multiple OSes going for long if it does produce a low-end Arm Mac that satisfies a lot of users? Is the Intel Mac market large enough to command focus?
Think back to the PowerPC to Intel transition. They managed that (largely) without fuss. That points to Apple being able to run the same OS on two platforms. Microsoft are trying same with ARM Windows machines though with less success using 32 but only emulation and compatibility problems. Expect Apple to do it full 64 bit all the way and pretty much seamlessly.
I’ll break from Katherine in saying I expect (if it happens) the ARM processors to start bottom end but to also cover up to the lower end of Pro.