Maybe someone who knows about brakes could post a cost/benefit analysis on disc vs drum.
The Fall 2004 Gazette from Toyota CANADA has the Yellow Cab in Vancouver, BC on the cover and a short article covering the two classic and one 2G Pri. At one point the owner, Andrew Grant, reported on PriusChat that he didn't have to replace his front pads until he hit 150,000km. I don't have info concerning rear shoes but conventionally there seems to be a 3 or 4 to 1 ratio on replacement of shoes so extrapolation puts the Prius shoes needing checking at 450,000km and replacing at 600,000km! :lol:
So while it could be an effort to maintain MSRP below a certain level I can't believe that's the whole reason. Maybe VSC is more effective with rear drum? Maybe regen braking is easier to engineer/implement? What's the percentage of regen coming from the front, if any, versus the rear? How much noxious stuff is shed when braking using pads versus shoes? Could just be me but I think there's more to it than economics. After all, in certain circles, this vehicle is touted as the most technologically advanced vehicle on the road.