I heard that story yesterday as well, and it made a lot of sense to me. It seems that for larger, denser regions (e.g., the Bay area, or here in metro Atlanta), one of the biggest issues is priority for public transport.
It takes an age and a day to get trains built anywhere, if they even make sense and you can muster the will to pay for them. Buses and streetcars can be cheaper and more flexible, but they're a net loss for riders if they can't outpace already-bad traffic. Sadly, we haven't figured that out here in Atlanta, so a bus commute is often at least double the equivalent car commute.
I've noticed that SFO at least has priority bus lanes (like I'm used to seeing in Europe). If you could extend those throughout the Bay area, and have "last mile" shuttles in places like MTV with similar priority, it seems that could work.