I disagree. On MacOS (x86) Docker runs inside a VM; which is running Linux (since Docker needs Linux kernel features). On the forthcoming ARM version of MacOS,

I disagree. On MacOS (x86) Docker runs inside a VM; which is running Linux (since Docker needs Linux kernel features). On the forthcoming ARM version of MacOS, it will need to run a VM, running the ARM version of linux. So having Docker working on the ARM version of linux is a good portion of the work needed to get it to run on ARM MacOS. You still have to get the VM and communications setup done, but Apple has already said they have done much of that work.