I remember seeing this map when it was new.
https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~315658~90084441:Silicon-Valley?sort=date&qvq=q:silicon%20valley;sort:date;lc:RUMSEY~8~1&mi=18&trs=50
and related, for your "how many still exist?" self-torture https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~329459~90097922:Silicon-Valley-