I've just come back from traveling, and multiple cities in my route had public transportation to/from their airports. Last stop was Ottawa where one can ride the city bus to downtown for $3.25 (further than YYT to downtown)!
I don't ever remember this being discussed by council or YYT admin, but it may well have been. The #14 bus already goes to Airport Heights and half way into Craig Dobbin Way!
Is there some collusion with taxi companies preventing this?
http://www.metrobus.com/systemmap.asp