When i worked with physical machines, they had embedded management systems, which were on a physically separate network to the machines' main interfaces, ran a little embedded SSH server, and would (amongst other things) give you a console on the machine.

Simpler machines should still have serial consoles, and you can get those on the network via a terminal concentrator or a serial-to-ethernet adaptor.

I would love it if Ansible could control machines over an interface like that, rather than via SSH. Then you wouldn't even need to run SSH on machines which don't need it, which is most of them.