But when we abandon most of the West (earthquake, fire, drought), midwest (flooding, tornados, east and particularly gulf coast (hurricanes), there's a whole lot of economic output lost from working land (farming, mineral extraction, etc.) that won't be replaceable when you crowd the remaining population into whatever safe bubble you have left.

The reason people live in dangerous areas is because they are often inherently economically productive, and in fact many of the things that make land suitable to human habitation are associated with periodic risk (freshwater supply and flood risk tend to go together, for instance.)