Back in the sixties, seventies and eighties there were far more travellers to Canada as a result of the large emigration that took part from Britain. This led to more frequent visits by relatives if these 'new Canadians ' as they went to see where their families had settled and to retain contact.
Now those Canadians are well established and the immediate family links are being lost as sons and daughters become grandparents etc to the UK generation.
Yes, Air Transat have good loads on their present frequency of flights but whether a daily service could be supported is questionable.