There's also this assumption that people in relatively segregated rich areas want to be connected to poorer areas via public transit - the opposite is more often true.
People who wish to live in neighborhoods with low crime often NIMBY off any attempts to add public transit options specifically to keep out the riffraff.
Marin County is home to over 252,000 residents, yet it is without a BART station. If you search
web content to find out why that is the case, you will not find a lot. There is minimal information
explaining why the BART doesn't connect from Marin to San Francisco and even less explaining why it
doesn't connect from the East Bay to Marin.
Marin funded a large portion of the project when BART was being planned in the 1950s. But "concerns"
over whether or not the Golden Gate Bridge could support BART suddenly arose. After San Mateo pulled
out of the plan, Marin's participation fell through as well.
It is not unfair to speculate that socio-economic discrepancies might have something to do with this
lack of transit connection. After all, Marin is the county where wealthy residents stopped George Lucas
from building affordable housing on his land. The median household income there is almost $84,000, more
than $15,000 more than San Francisco and more than twice as much as Oakland.
A similar situation in Dayton, Ohio arose where wealthy suburbanites tried to stop the local transit
authority from building three new bus stops near major employment centers.[1]