Systems that are installed and not monitored
When signs blow up, they are of course visible.
But all of these BORKage articles seem to be the low hanging fruit. Like, as IT professionals, are these systems high priority? Or pretty much the lowest priority.
If they fail, the business effect is minimal. To perform maintenance on them can be a pain, they might not even have a remote access connection. So of course they die, eventually.
A system that is not rebooted regularly will eventually experience an outage at an undesired time.