For sure natural disaster can take various forms, and even if we took several precautions in regards to our private keys, we might have had made mistakes, so for example, maybe in the LA fire example, we had some kind of a hardware wallet, and we had back up keys in our house and then another set of back up keys in another building on the property (if we are so lucky as to have another building available to us, such as a shed or a garage), but then if our backups are on paper, then they might have all gotten damaged.. and a similar thing can happen in a hurricane or tropical storm zone in which the kind of disaster is different, and potentially leave us vulnerable if our backups are not sufficiently geographically separated.
Some people do not even have access to any location other than their living location, which might not be a lot of places to store/hide backups, and surely the more value that we hold, the more important it becomes to spend more time and potentially money in protecting our value.
Surely with some of the burnt homes there might have been people storing a lot, if not all of their wealth in their houses, and so then if their house burned down, they would likely needed some kind of an insurance policy, since it could be difficult to self-insure.. and if a person had residential property and also had bitcoin, then maybe they ONLY lost half if they had secured the bitcoin properly, yet surely it is difficult to presume that everyone who might have had bitcoin in the fires had secured their bitcoin sufficiently (or maybe they got lucky and their backups did not end up getting destroyed... or maybe if they had notice before they evacuated, they were able to take their backups with them?)..
Surely there can be a lot of kinds of value besides the personal residence or the bitcoin, and also some folks put a lot of time and energy into building and organizing their personal (and perhaps work?) space, and so there could be a lot of loss in regards to various organization systems that a person might have established in their personal residence.... There could have had been value in having had built neighborhood relations too.
So that led us to the big question, since we can’t feel safe secure our backup phrases online due to fear of hackers and online theft, and neither can we feel completely safe securing our backup phrases offline for fear of losing them to thieves and natural disasters, where/what then is the safest place or method of storing our wallet data, where we can completely feel safe without having to worry about threats?
To answer your question, nothing in this world is 100% secured, anything is possible.
We live in a world full of uncertainty, no one knows what may happen in the next few days or month because nothing is promised, the best you can do is to save your secret phase offline and leave the rest for God, because to the best of my knowledge, it's only God that gives 100% security.
If banks and most of these exchange that has everything to protect themselves are being breached on several occasions, tell me what makes you think that you are more perfect than those institution on security?
You might even decide to have several copies of your secret phase in different geopolitical area of your country just as suggested, they might be protected against natural disasters, but have you thought about it if one of it falls into wrong hands?
Any of them lost will definitely be a serious security threat to your asset, so in essence of all am trying to say is that their is no perfect security when it comes to this world that we live in, the best way to protecting your holdings right now is saving it offline on a single sheet, and leave the rest to God.