As a retired Los Angeles fire captain, who spent many days fighting wild-land fires, I believe there is more to the problem than meets the eye.
Obviously wood roofs are the cause of more extensive spread of fire than other less or non-combustible types. So why do so many homes have these roofs? Why do legislators (city, county and state) refuse to enact laws prohibiting or restricting them?
I believe the answer may well be the lobbies for the wood shingle and split wood shake industry.
I attended many meetings with these people and you should hear them defend their products. They are so blatant as to practically refute nationally recognized statistics about the danger of their wood products.