as a side topic, ever notice that most sci-fi is canadian in origin? Bioware is canadian. BSG and the Stargate series have a strong canadian flavor.
You realise that you only refer to contemporary sci-fi, which is tremendously watered down in intensity when compared to the '50's, the "Golden Age". There you had Asimov, Clarke, Bradbury churning out thought provoking and exciting "hard" sci-fi like clockwork. You had Herbert exploring religion, Vonnegut's unique satires, Wyndham's take on a flora-apocalypse, etc. etc.
These people aren't Canadian, and didn't live in Canadia.
As for TV shows? It's simply cheaper to film in Canada. See X-Files for prime example of TV series economics.