Although I think there higher priorities than Sheppard, comparing it's current less than stellar ridership level to reinforce the idea that it is a waste of money is disingenous.
When the Spadina is completed the transit traffic on Sheppard will soar as YorkU is the second largest transit centre in Toronto. A Sheppard line ext to Downsview or conversly to STC would not only actually serve thousands of more residents but actually get them somewhere. If it becomes one thru route from Downsview to STC the line actually serves not only thousands but also 2 main transit connection centres.
Also the said savings of $1 billion should be easy enough considering how the TTC think 2 km of suburban subway could cost nearly $1 billion...........an offensive amount.
That would be one very good result of making this a PPP........the private sector would demand value for the dollar, it wouln't build any $400 million subway stations a la Spadina, and it would be a more accountable contract. The great thing about the Canada Line is that the price and timeline were set as was station designs, routes, etc and any time or cost over runs would be 100% the financial responsibility of the private partner. None of this "escalated dollars" crap you get from the TTC.