Except amenities and opportunities don't work on population percentages, they work on raw numbers. A city of 230K has more opportunities and amenities than a city of 25K.
Most of the Canadian population lives between Sarnia and Quebec City. An area that has a population density that is close to what much of America has. That means the average Canadian doesn't live in a city of 25K in the middle of nowhere, regardless of landmass.
If the CAF wants to put a full base up there, the bonus we pay will need to be large, meaning less money for other things like jets, ships, artillery, etc...