Bay Area mass exodus of residents leading to a shortage of U-Haul trucks
aei.org
aei.org
Similarly, there could well be a shortage of U-Haul trucks if the people arriving are young ones with no more than a car full of possessions, and the people leaving are older ones who've accumulated lots of stuff. But that doesn't seem a sign of decline either.
And as I understand it, there's room for quite a bit of this to happen in the Bay Area. There are plenty of stories about really dramatic numbers of people cramming into two-bedroom apartments.