American, living in area prone to natural disasters: "Is the WHOLE WORLD becoming uninsurable?" The answer is obviously "no" since there are other parts of the world that don't live on a hurricane highway nor build houses made from firewood in an area prone to wildfires.
It looks like it's a reinsurance program:
https://www.mof.go.jp/english/policy/financial_system/earthq...
So, I think the answer is "no".