This article touches on the accepted justification for expanding the league by choosing US cities such as Las Vegas over say Saskatoon, Saskatchewan, which that

This article touches on the accepted justification for expanding the league by choosing US cities such as Las Vegas over say Saskatoon, Saskatchewan, which that in the USA you have this huge possible range to grow, whereas in smaller Canadian centres hockey may be hugely popular, but its possible that the NHL is already reaching all the hockey fans they'll ever get and there's little room for growth. The question of whether there's any room for further growth in hockey popularity in Canada is being tested right now. Rogers Sportsnet just bought I think 10 years of exclusive hockey broadcast rights in Canada and I've read some articles that state that Rogers will need to increase the amount of people who watch hockey for this endeavour to be profitable. To start they've already cranked up the total number of games that appear on TV. It's going to be interesting to see if they can move the needle.