Old houses in rural areas often need a lot of care due to their age and condition. They may have sat empty for several years and suffered damage from a lack of maintenance.

Also if they're cheap postwar construction, they may not be very earthquake safe. If they're older traditional architecture, they're probably ok but still probably need a lot of TLC.

Because it’s the (outdated) law due to earthquakes. Building and materials have gotten much better since the original laws were passed.

Are you required by law to build a new house? What if the house was just built a year ago.