The Airlines fly routes that make the most profits / has demand. In Canada

, Toronto YYZ , Vancouver YVR and Montreal YUL & Calgary YYC is where they make the most money & where the increased or new flight frequencies are

.
For cities like YEG, Halifax YHZ, Ottawa YOW, Winnipeg YWG etc , that are non hubs is tougher to get new routes every year.
Plus after Covid19 pandemic, a lot of airlines

are still consolidating their routes to make them more full through their busier hubs

. A pretty good example why the Edmonton YEG - Hamilton YHM route still hasn’t come back yet as WestJet rather consolidate it through YEG-YYC-YHM.