Not quite six years ago, wildfire expert Jack Cohen, who lives in Missoula, Mont., visited Pacific Palisades to instruct firefighters and property owners on how to protect homes against wildfires. Three days of training, including a tour of the community, left Cohen hopeful, but the feeling faded when it became clear that his lessons were not going to be fully implemented. This week’s tragedy has left him with a deep sadness. Respected by fire agencies across the country, Cohen and Pyne have found their straight-talk admonitions often disregarded or dismissed. Sensitive to losses and suffering, both said they are motivated...