Why So Few Canadians Live In This HUGE Area In The Middle Of Canada

Canada, much like the United States, is split into two halves. On the east side is Canada's major population centers of Toronto and Montreal. And on the west side are the smaller, but still large cities of Winnipeg, Edmonton, Calgary and Vancouver. But separating thw the two halves is a VAST EXPANSE of almost nothing, comprising what I've termed Canada's Empty Belt. So why don't more Canadians live in this area specifically?