ILOM/iDRAC/etc largely solved that sort of thing, but there was always a chance that grub config became corrupted eg when upgrading kernels, leaving you with a 4-hour drive. Pid 1 is critical, and it's ridiculous that it took until systemd for it to stop being something that was just hacked together instead of a well-supported (if surprising at time) software package. It was a real "cobbler's son has no shoes" moment when I first realized back in the RHEL 4 days that the /etc/init.d/ scripts I was looking at were the actual implementation and not some abstraction.