Redundancy matters when it protects from plausible issues.
> Hospitals don't stop carrying backup power supply for life-saving equipment just because "the power grid downtime has improved."
When power goes down, there is an immediate harm to patients. The grid downtime would need to be really implausible. Also, batteries would probably be okay now.
When fire happens - which is rarer now - it also rarer blocks the exit in a way that causes harm now.
Good example is ETOPS - https://en.wikipedia.org/wiki/ETOPS - some time ago, we required flights over ocean to have three or four engines. Now, reliability improved a lot, and the engines got good enough that single-engine operation is not so catastrophic as before.
> Hospitals don't stop carrying backup power supply for life-saving equipment just because "the power grid downtime has improved."
When power goes down, there is an immediate harm to patients. The grid downtime would need to be really implausible. Also, batteries would probably be okay now.
When fire happens - which is rarer now - it also rarer blocks the exit in a way that causes harm now.
Good example is ETOPS - https://en.wikipedia.org/wiki/ETOPS - some time ago, we required flights over ocean to have three or four engines. Now, reliability improved a lot, and the engines got good enough that single-engine operation is not so catastrophic as before.