Remember, streaming bandwidth costs money. In a country of 35 million people, to have 320 million next door possibly drawing on their bandwidth, that's an imbalanced traffic flow / cost. But for American services, having a few extra canadians using their bandwidth isn't a problem. Mostly it's about rights though. CBC does make some of its news programming available worldwide, but not their comedy or fiction. Schitt's Creek is the only CBC show I know picked up by a U.S. network.