I think what you might be missing in your analysis is that preventative approaches that only "stop" the spread of fires only contribute to reducing the occurren

I think what you might be missing in your analysis is that preventative approaches that only "stop" the spread of fires only contribute to reducing the occurrence rate of catastrophic events, but also contribute to increasing the severity of them as well (through build up of fuel). Robust solutions should ideally both manage occurrence and severity of catastrophic events, and be able to scale through multiple magnitudes of risk. With the limitations we have, we're typically stuck with really only managing one of those levers - but we should absolutely hesitate from solutions that increase severity. We should be spending money scaling our ability to actively fight fires once they start, but that doesn't mean we shouldn't also spend money and resources to try to reduce the scope and scale of fires that we do need to fight.