I think that is part of the problem. Probably a huge part. If you’re really talented, the assumption is that you’ll head straight to the states (perhaps after cutting your teeth on a few Canadian shows). The people who stick around and exclusively do Canadian stuff aren’t all here because they’re patriotic. Based on a few conversations I’ve had with Canadian actors, most of them would kill to be getting American work (and getting paid in American dollars. Even with the dollars being at par, I think you generally get paid more for US TV and movies). On the other hand, if you are a working actor in Canada with a good rep you can count on paying the bills and then some by being cast in every movie that’s got Toronto standing in for some other city, whereas there may be more competition south of the border.