I have some sympathy for the conservative position on light rail. The real questions is can LR keep Seattle livable and avoid the endless panorama of ticky tacky suburbs that afflict most of the US??
LR is like a river ... it forces development along its banks. Roads, esp with good bus systems, may be lot more efficient since they can go anywhere. Kind of like enhanced walking.
OTOH, light rail is more like a teleporter. Its main function is to connect two, fixed locations.
I see the main value of LR in connecting the U District and Downtown to Seatac. When I am in cities with a good subway, the physical location of a building seems to disappear since I can get into a teleporter/subway and move easily from one place to another. Paris, Boston, London, are all like that.
I think Goldy is too romantically attached to LR. The worst of all worlds may be New York. The combination of good subways has created a rats nest of overpriced high raise AND an oil slick of suburbs.