But you can't treat those details, the restrictions on growth, the way that poor people were pushed into substandard locations that only now face demand, the lack of new housing elsewhere, as something that just happened. These are systemic issues.
Nothing about this has just happened - if you read the article, they even have a link to a 1994 article in the Christian Science Monitor about the divide between East Palo Alto and Palo Alto.
Rent control ordinances in East Palo Alto probably help the current community stay in place (unlike other Peninsula towns).
The article also explains the role of subprime loans (in the context of refinancing for existing homeowners) in causing a loss of home equity with the existing community, especially between 2003-2008, which was in-between the booms in the SF Bay Area.