In New Zealand after the Christchurch earthquake, the government condemned entire suburbs and made it illegal to build there.

They then initiated an inspection of every multi-storey building, and allocated an NBS rating. Some buildings were condemned, and other buildings must be strengthened. It's almost impossible to sell these affected buildings.

So in the US for a national insurance scheme to work, the government would need to actively remove high risk properties.

New Zealand also has no state governments, just one national government. So it's much easier for them to implement these sorts of policies.