The surroundings of Vancouver are pretty populated. Cities such as Burnaby, Richmond, Surrey, Langley, White Rock, and Abbotsford. Add that up, you get 2.6 million. Kamloops, Kelowna and Victoria are short flights but driving can be far.
Toronto alone has 2.7M. The GTA overall has around 6.2M. That doesn't include Hamilton, Kitchener, Cambridge or St. Catherines, which probably are an additional 1M and aren't that far of drives as well. So you probably have a little over 7 million people all within an hour or so from Toronto.