There is a limit to how much it is practical to prepare for something that will never happen. If we all lived like stone age cavemen and put all our earnings in savings/safe investments we would all likely die millionaires. But who wants to sacrifice all quality of our current life for some distant time? So we spend enough to make us happy and satisfied as we have it even when we are responsible and save something for emergencies and for our future.
We don't build fireproof structures or hurricane proof homes because the cost is more than it is worth to us. But we can lessen the risk with fireproof roofs and strengthened walls and such.
We don't build essentially safe automobiles in which we would survive almost all auto crashes because the cost is more than we choose to accept. But we do pay extra for those seatbelts and airbags and firewalls and roll bars and antilock brakes that make autos a lot safer for us.
We accept some unknowns and are willing to gamble to a certain degree and are willing to give up so much current quality of life. So cities/states can prepare for ordinary fires, even wildfires that we know will occur at times. But fires of the magnitude California is currently dealing with, nobody could be completely prepared for.
We can prepare for bad storms, tornadoes, hurricanes but nobody can anticipate much less prepare for the magnitude of damage of say a Katrina or the North Carolina floods caused by Helene. We can fault no mayor or governor for not being prepared for something like that.
But we sure can fault public officials who don't do what is normal and reasonable to minimize damage when they know how to do that or are told how to do that. We can certainly fault public officials who are negligent in doing what they can to reasonably protect the public.