Its impossible to know with certainty how many franchises Canada could support. I think 9-12 is reasonable.
Southern Ontario could support two more teams; another in Toronto and one in the Hamilton area. There are tons of major corporations with deep pockets who could buy suites. And there are more than enough fans in the area to support three teams. Anyone who says otherwise has probably never been to the area. Now, will it happen? Probably not. The more teams in the area, the worse it is for MLSE. That doesnt just impact the Leafs, but also the Raptors and TFC. If people have more hockey options, they may spend less on the other sports. Which wont make MLSE happy.
I dont know Montreal or Vancouver well enough to know if second teams would work, but much like Toronto, with the numbers of corporations there, and the size of the cities its logical to say additional teams could work.
Winnipeg is obviously back, and Quebec City should get another go, hopefully by 12-13.
Someone compared the Habs to the Yanks. If I recall correctly, I believe another baseball team has managed to survive in New York along those very same New York Yankees.
Did Atlanta fail as a market? Yes! Twice!!
The overall issue about the sunbelt is not fair in the sense that every market is unique. They each have their own issues that will dictate success or failure long term. I think the overall point is that when Gretzky was traded to LA, the league took to trying to make hockey a legit sport in the southern US. They expanded or moved teams to these new markets, and we're slowly seeing who will last.
I'm a believer in putting teams in places where enough people like hockey. And not just fans who will only go if they get 20% off their hot dogs, or if the team is doing great; I want real passionate fans. I watch tons of games throughout the season, and there is a correlation to bigger/enthusiastic crowds and colder temperatures.
Someone said it shouldnt matter if you're from a place where the pond freezes over in the winter. But that totally does matter. Thats why (hold on to your hats) the best hockey nations are generally cold climates. You grow up with the frozen pond, you learn to skate at 2 or 3, and you've got a hockey stick in your hand soon after. I'm guessing that doesnt happen very often in Atlanta, or Sunrise, or Tampa, or Dallas, or etc etc
I wouldnt get offended if some American tried to explain to me that Canadians dont have the same love of baseball or football because its not such a huge part of our identity. Does that mean every city in Canada can support an NHL franchise? Of course not. But it does mean that all things being equal, the Canadian city will support their team better than the comparable American city. Anyone who doesnt get that is dense.