controlled burns require weather conditions that allow them to be done safely, as well as people knowledgeable enough to keep them controlled. and the amount of the time in the year when temperatures are cool enough and the ground is dry enough keeps shrinking. controlled burns are only really a solution for a very small percentage of a space as big as california if you want to do them safely. What they sometimes do up here in canada is just monitor and let the fires burn out of control as long as they're not moving towards a populated area, to reduce fuel in a large area. but you can only do that as long as the area is truly unpopulated, if one person builds a cabin in the woods you have to move to suppression.

as i understand it, there's been a fair bit of progress in the last couple years regarding best practice for wildfire protection in populated areas. you can do a lot by removing underbrush and building firebreaks around a town, as well as relatively simple measures like disallowing cedar-shake roofs. there's probably a future where properties in towns that implement strong wildfire protection plans can continue to be insured, and towns that don't cease to exist. but that only solves the problem for towns, i don't see what can be done for properties in the woods outside a town's firebreak.