Earlier quoted context omitted.
Exactly this. North San Jose (the 237 triangle) used to have PCB, chip, chassis, component, etc., manufacturers in proximity to each other. Consider: Sun used to make and assemble their "workstations" over in the East Bay not far from the 237 triangle. As the late '90s approached much of that local manufacturing was off-shored to the Foxconns and Flextronics, etc. as well as overseas foundries.
As a consequence of all of that concentrated manufacturing, Silicon Valley is now a cluster of EPA superfund sites. https://en.wikipedia.org/wiki/List_of_Superfund_sites_in_Cal...
https://upload.wikimedia.org/wikipedia/commons/9/91/Superfun...