Is the world becoming uninsurable?

Every era has it's Malthusian alarmists and without fail, each has been proven wrong by exactly the same thing the author decries and says won't work this time: technological change and adaption. There's no reason to think this time will be any different. Will some places become uninsurable? Sure, plenty of places over time have become uninsurable. Will the whole world became uninsurable? Absolutely not, because we are quite good at adaptation in the face of adversity.

The issue in California is not the price of insurance, it's availability because of extremely myopic ballot initiatives that are entirely political in nature. Should insurance be fairly priced, then the market can force people out of uninsurable areas and into areas with far less chance to burn.

You can't live in places where your home is going to get destroyed every couple of decades by wildfires, floods, or hurricanes. There are more of these places now because of climate change and a lot of people are going to have to migrate over the next century, like huge global migrations. Insurance can't/won't allow a bunch of people to deny this reality any more (or at least much longer). LA is going to be pretty uninsurable unless the local governments do a lot to mitigate the fire risk.

You can; it's just expensive.

So is living on the sea bed. It's irrationally expensive and inconvenient, which is why we don't do it.

Living in areas in constant danger of flooding and/or burning and/or storm wind damage and/or drought seems like quite an eccentrically inconvenient lifestyle flex.

Unless you like disaster movies.

Where are you suggesting we live then? Most all of the US is at "constant" risk for at least one kind of disaster in your list or another.