Re: No choice really.
I used to rent a place 1500 feet from that trailer park and passed it every day on the way to work. It isn't earthquake liquification land, but just a historical oddity.
Trailer park rents very strictly controlled; Palo Alto itself completely forbid any rent increases at all 14 years ago. At the time, the place was run down and needed improving; it's simply gotten worse. To put it in perspective, rent for a nearby 1170 square foot 2 bedroom apartment (1960's construction) is currently listed $3400/mo, and I paid $1600/mo for 800 square feet during the last recession (also 1960's construction, in all it's ungrounded outlet glory). Current trailer park rent for a single-wide mobile home spot (single-wides area maximum of 1600 square foot but sizes can widely vary) is ~$750/mo.
It currently houses 117 units; the original plan the owners proposed was to replace it with 180 condo units. Yes, they were clearly going to be unaffordable to the current residents, but the problem isn't a lack of *affordable* housing, it's a lack of *any* housing. There is a large enough segment of Palo Alto voters who disagree with any change that the land use has become insane. Consider this lovely empty lot at 575 Maybel Avenue (https://goo.gl/maps/CfKU5)... Palo Alto voters explicitly shot down a plan for 12 single family homes and 60 units of affordable senior housing 2 years ago. So instead of, say, 100 people having a place to live, there is still a fenced-in weed filled lot. Or consider 4146 El Camino Real (https://goo.gl/maps/RRo24)... Google Earth shows it in one of the few times it's ever been plowed, but it's about an acre of fenced-in weed-filled lot, and except for a lone billboard, has been so for over a decade.
And both of those are within a kilometer of the trailer park.
Palo Alto, the Bay Area, and California have a bad land use problem. It makes no sense for a place as run down as 3775 Laguna Ave (https://goo.gl/maps/WeIHQ and it looks a lot worse in person) to be worth an estimated 2.2 million dollars. London has a terrible affordability problem, but at least in London people renovate their dearly valued buildings and go denser. Palo Alto seems to want to stick with single-story separated houses (with minimal attempt to upgrade the quality from the shoddy post-WWII construction binge) for all time.