How many fires has California been through? Why aren’t there mandatory slate roofs yet? In this picture there are homes standing amongst the devastation. There is only reason, non-combustible roofs.
This shows up with every major fire. People still have to evacuate and there is smoke damage and property damage so some extent, but, they have a home to come back to. In the long view the extra cost in the structure and the roof pays off.
Fire embers come down from the wind like rain.
Wildfires will burn at an alarming excess of 1472 degrees Fahrenheit. That means any clay roofs will melt and allow fire to take the structure. Roofs, Spanish style or otherwise, made of slate have far higher resilience to catching fire.
Some states are seeing insurance rates that are unsustainable for homeowners. The wealthy can always self-insure, but, others cannot. Hurricanes are more destructive, tornadoes occur in multiples, and the land is droughted and susceptible to fire.