A tepid launch of Amazon.com Inc.’s Prime video streaming service in Canada doesn’t seem likely to pose a challenge to existing players in the Canadian streaming market — for the time being, at least, given Amazon’s global clout could make it a formidable challenger in the future. Amazon’s quiet roll out of the service last month, combined with a small library of content, makes Troy Crandall, an equity specialist at Raymond James Ltd., skeptical that the launch of the streaming service has led to a lot of new subscribers for Amazon Prime in...