It’s similar to building in flood zones. Land that has no potential natural threat has been exhausted over 50 years ago. What is left are areas that has natural threats. Unless you want to stop building near population center your left with mitigating the threats and then building
Use building materials like hemp or other less flammable.
One big difference and facts you left out. The defensible space between early subdivisions and Santa Monica mountain range. It was developed on and no defensible space was left to defend homes. It was a continual homes in side the defensible space.
A suggestion - perhaps we might run water pipes up into the hills, controlled by heat sensors: systems that could detect small fires, attack them, and warn the citizens below. It would seem less costly to install such a robotic system than to replace a whole city.
Many of the homes in the "Alphabet streets" section of the Palisades had been there for 90 to 100 years and had obviously not burned until last month. The fire could have been stopped within minutes of its start if our firefighters had been staged and ready to act when smoke first appeared. They were not. What followed was the result of not being prepared to move when it could have made a difference.
@flashback0978