Could you make a similar statement in 1970 about Detroit?
Toyota, GM, Ford, Chrysler, Nissan, VW, and all their parts suppliers(and the supplier parts suppliers) have at minimum a white collar office in south east Michigan.
The event that caused the Exodus from Detroit was the Race Riots. You can Google that because I'm not touching that topic.(and it doesn't help Detroit has a 1% tax)
Similar thing can happen to SV. People moving to "suburbs" -> other parts of CA.