My brother-in-law and mother-in-law, in separate communities, were affected by those fires, my BIL being briefly under an evacuation order. They were welcome to stay with us, only a little over 100 miles away, and under no direct threat from existing fires. There was plenty of motel/campground space in our community throughout the incident.

Half a million refugees (peak figure) is still only about 3% of the total SoCal population (very roughly 16 million).
I have no idea of what the capacity of the motels in the area might be, but most of those half million had friends and/or relatives, so perhaps this illustrates the value of relationships in survival situations, the subject of another current thread on this forum.

I have been in my residence for over twenty years, and I have been focused on earthquakes as the main threat during that time. However, on two separate occasions, I have had the car loaded up with the items on our priority list, ready to move as the hills behind our residence burned. With a full tank of gas, and reasonable self contained gear, the plan is to drive until the air quality improves and find a place to stay. Shelters are not appealing, and are fairly far down my list. That is not to say they aren't useful and I am sure they fill a definite need.