Wow, I really appreciate that anecdote. There are historians of the Bay Area who research those sorts of things.
From what I gather, many do consider that the WWII concentration camps for American citizens of Japanese ancestry was a racial terror on Bay Area residents comparable to what happened in the 20th century South.
Anyway, after covenants ended, for several decades developers and real estate folk found it legally, politically, and financially expedient not to sell to certain minorities. Want that subdivision project to go smoothly and sell quickly? Apparently in many cases it was optimal to subtly or not so subtly advertise exclusionary sales policies.
So you see, there were not as many Black Steve Jobs or Mike Markkula as their could have been -- because certainly as late as 1960, a Black teacher or firefighter or qualified professional would have found it relatively difficult to relocate to Mountain View or San Jose as Steve Jobs' own parents did. And this robbed minorities out of participating in the economic engine.
This was not special to Santa Clara county, as it was common practice all across the nation.
But because SV has such poor commuting conditions for any relatively proportionate critical mass of Black Americans, particularly those who are descendants of slaves, the exclusionary effect is quite extreme and one really can't purport to care about diversity by locating there.
By comparison, an economic engine like Wall Street is a modest subway fare away from literally some of the poorest census tracts in the nation that are located in the Bronx. Which at least in theory allows a poor kid to work up from the mail room, and does not by geography alone minimize opportunities for poor minorities.