I agree with you that there's many device in that range, but why are they not well served by using an operating system? When is a device large enough to run the whole Go runtime but too small for (say) Linux?
Compared to a complete Linux kernel, the Go runtime is pretty tiny.
Buy to your point there is no magic answer. The question is rather: when is the capabilities of a full OS kernel like Linux worth the resources needed to run it? And the answer is ultimately: it depends.
