In the USA I think a big driver is that even though natural disasters occurred in the past, the federal government would bring the resources of the nation to rebuild those cities. trump and his administration are regularly denying federal aid. Insurers are are also fleeing states with climate risks causing rates to increase or leaving expensive and state supported "insurance of last resource" becoming more of the norm than the exception. So those that need to rebuild are burned and don't rebuild in those cities, and others see the writing on the wall and are selling their properties and also moving inland while their homes are still standing with value.