The problem is that the need is spiky. You don't need many of them until an old apartment building or factory catches fire because of cladding made in the 70s.

They are like seat belts, or audit logs. You don't need so many of them, right up until you do.

Mass casualty events are rare, but you damned sure want a good response when one happens or the losses will be high. It's a never ending cycle that people seem to suffer from.

OMG so many people died, we need to spare no expense in insuring this doesn't happen again.

[time passes]

OMG these emergency services are so expensive, why do we even have them.

[budget cuts, size cuts, personnel cuts, cuts cuts cuts]

OMG, I'm on fire, everything is on fire, why did the state do this to me, we need to spare no expense in insuring this never happens again.

Ahh yes, the old "why do we have all these inefficient empty hospital beds???" problem.

On a fundamental level, efficiency and resilience are always a trade-off. A perfectly efficient system also tends to be perfectly brittle! In practice everything needs some buffer.

We shouldn't aim for "as close to 100% efficiency on <metric> as possible," but rather "lowest risk-adjusted expected cost, including mishaps." The latter correctly prices rare events.