When I moved to San Diego in 1981, there was little mention of wildfires or living with wildfire during that time. The population of the area was a lot smaller than it is now and fewer people live in the back-country. There were still large stretches of undeveloped and uninhabited properties throughout the county. Most of the population was in the urban areas.
The first place I moved to in the San Diego area was on the edge of a canyon. There was a small “river” (more like a trickling creek) that ran through it. Sometimes, there would be fires in there, usually caused by migrants passing through or kids playing with matches. They were mostly small and quickly put out. I think I only saw one that was even close to a home. The first few years I was there, we had an El Niño season with a lot of rain and that river canyon flooded. For a while, there was lots of water in there and fewer fires.
It seems like any brush fire I heard about for years afterward was either caused by someone throwing a cigarette out a car window or some kind of illegal activity. They were mostly kept small and usually were out in an hour or two. For the last ten or twenty years, it seems like there are fires everywhere, every year, and they can get quite large.
In 2003 and 2007, there were fires in the area that lasted for days and burned for miles, not just a few acres. Since then, San Diego has improved their firefighting resources and many of the fires often kept to just a few acres for only a few hours. But, things still seem worse than they were when I first moved here due to the population problem. It would seem that all of the eastern part of the county, except for the deserts, is at maximum population density. Most fires that start in the area are a potential threat to homes. A persistent and increasing drought is also a contributing factor. But, that’s a whole different story.