As to the BART SF Airport extension - interesting, but as they say in my old country one swallow does not bring the Spring. Airport is one thing, but I doubt that these suburban rats would allow any public transit in their back yards.
A few months ago I attended a public transportation planning meeting in Baltimore, and the biggest complaint was insufficient parking followed by requests to remove bus stops which "take" two-three parking spaces. That mentality widely spread among the US public. I have to admit, however, that a surprisingly large crowd demanded expansion of the transit system, even though there is no political will in Annapolis to do so.
To be fair, I must admit that the US population is more or less evenly split between Repug-voting suburban or rural fatheads who hate anything public, and a more urbane liberal crowd that would welcome public services (but not at the expense of their own comfort and convenience.
PS. When the revolution finally comes, all suburbs will be bulldozed and converted to public parks and farming coops, and their inhabitants sent to reeducation camps where they will be trained as bus drivers, train conductors, and public housing maintenance workers.
Wojtek