Slightly more than 100,000 people in 3,867,271 km^2 of the 3 northern territories. (Just under half of Canada by area, bigger than India) It's going to be very hard to assert sovereignty when it's such a large area to monitor with so few people. For example a German weather station build in Labrador in 1943 wasn't found until the 1980s. Who knows what other countries are already doing in Canada's north.