There's no natural affinity between the two cities so not enough yield to dedicate an aircraft for a half-day on the route. Much more efficient to feed customers down to YEG or YYC and then to YVR or other points. The YMM non-stops eastward work because they save travel time for the many thousands of Nflders who work there an "commute" home to families frequently. Of course, if you could line up 1400 others who want to go to Vancouver every week, AC or WS might consider a non-stop. Of maybe 60-70 and charter a plane each way each weekend.