I think the point here is it's not practical to build enough lanes to ever saturate demand someplace like LA, so it would make sense to build other options besides driving your car everywhere (and then make these options more attractive than driving). These will of course induce demand of their own, but it's easier to meet just because each person traveling in his own car is one of the least space-efficient means of getting around imaginable. That's not necessarily a big deal in the middle of the day, but at rush hour, with countless people heading in the same direction, it doesn't necessarily make sense to keep doubling down on the same strategy over and over.