First, wood shake roofing has been illegal in new construction in California for at least a decade. In some jurisdictions it's been illegal for a lot longer.

Fireproof roofing is a good idea, and the transition has saved a lot of housing. But, it doesn't make a house immune to fire.

Most houses in California are stucco. Stucco houses will burn, under the right circumstances. If sparks can get under the eaves or through any kind of ventillation, the house will still burn. If it is right next door to a house that is fully engulfed, the radiant heat will still ignite a stucco house. If the windows fail, as they sometimes do in these fires (especially vinyl windows), sparks get inside and the flammable inside of the house will burn, burning it down from the inside out. Indeed, even if the windows don't fail, radiant heat through single-paned windows can ignite draperies inside, with no spark.

Building codes have been very successful in saving some communities in California. Some jurisdictions are very strict and this has paid off. Every jurisdiction in every state that is vulnerable to wildfires should adopt these practices for new construction. It helps.

The new houses will almost certainly be an improvement for fire defensibilty over the old.