This was just the time my wife and I purchased a slide-in truck camper. In my view, a truck camper is a perfect emergency shelter. We keep it fully fueled, with full fresh water tanks, and fully stocked with provisions. The camper has a built-in generator, solar chargers, 50+ gallons of fresh water, hot shower, kitchen, comfortable bed, fridge, freezer, etc. It sits in our driveway. It is fully mobile - it can also go anywhere the dually truck can go.
We've had to use it as an emergency shelter twice now because of ice storms knocking out power to our home and neighborhood for days at a time with ambient temps below 15 degrees. I keep 5 extra propane tanks in my shed along with extra water and shelf stable provisions.
In the next month, we are going to install a transfer switch on the breaker panel in our house that will allow us to run the house from the camper generator. It will be limited, but we will be able to keep the furnace and fridge going.
Nobody I know who owns an RV sets it up as an emergency shelter. I don't know why - but the threat of a major, disastrous earthquake is very real. Further, many of my neighbors were ill-prepared for the most recent major storm two weeks ago (despite plenty of warning) and grumbled a lot about the city falling down on its job. In a major earthquake these people are going to be desperate and many people will die. The city will be broken and if you rely on emergency services - you are going to be lucky to survive.
I'm not a prepper. We bought the camper for off-grid camping in remote wilderness - but I do believe in common sense preparation for "The Big One". Despite the flurry of attention this article created in 2015 - most people have put it out of their mind.