In 1996 the original Winnipeg Jets left Winnipeg for the vast deserts of Arizona after there was no local ownership organized enough to buy the team by the time the NHL needed them to be ready to buy. The Nashville Predators were close to the same fate as the Winnipeg Jets except the script changed. When facing the fact that their local NHL team might be leaving local business owners rallied together and were able to put together a counter-bid to stop Jim Balsillie from buying the team and moving them to Hamilton, Ontario.
There is no single way to decide what is a hockey market and what is not. There are so many external factors that lead to the NHL failing or succeeding in any given market. There are corporate ticket sales, the local economy tanks, the team is terrible for a long time, or ownership does not care about the team at all. Any of these factors can help sink a team in any market, let alone where hockey was not always a part of the fabric of the community.
The Predators got lucky because they had local business owners who were able to step in at the eleventh hour. Other cities were not that lucky. Take Atlanta: their ownership group, Atlanta Thrashers, were only in it for the basketball team and it showed with their neglect towards the Thrashers ultimately lead to their demise. Atlanta Spirit refused to sell the team and they refused to spend money on the team; they simply refused to do the work that needed to be done to keep the NHL in Atlanta.
The fans in Nashville are proof of carefully following a plan and making smart moves when they are presented is a great way to build a sustainable fanbase. Nashville was able to grow the game in Nashville and Tennessee in a way that made the team the regions own. They were able to develop their own traditions like throwing a catfish on the ice or some fantastic taunts that are not at all sexist. This is all happening because the NHL was willing to stick it out in Nashville while a market was established. Hockey can and should welcome any market that works and Nashville showed that with the right people helming the ship, they could make a great market in a place that most Canadians did not think of as a hockey town until these playoffs.
Nashville has worked because of the will of people who were willing to fight to keep a team in their city. This is why Atlanta failed twice and Winnipeg lost a team once. Nashville had the business people who were able to rally together quickly enough to keep the team there and those business people were able to see that there was not a lot to change about the team, leaving David Poile alone to build his team. And he has paid them back handsomely for their patience. Think of the last time the Predators were talked about as a team with bad attendance or a team that was in trouble. It has been a long time and that is almost certainly because local ownership has been able to stabilize the team and the market.
Just because a NHL team is based in Canada does not mean that the team will succeed and just because a team is based in a city that is not traditionally a hockey market does not mean it will fail. Instead, local ownership, a unique hockey community, a local economy that allows people to have enough money to invest in the team, and an acceptance of fans from all walks of life are key to any team finding success and Nashville is a perfect example of this. Unless all these different factors are found in a community hockey will most likely fail.
Nashville is a unique hockey market in the sense that unlike other places that lost their teams, they had local saviours who were able to move in and keep the team in the place that was falling in love with hockey and the Predators. It has nothing to do with where it is located and everything to do with having people who care about the team owning the team and ensuring that success can be found by caring enough to okay moves that will help the team win without over-reacting to losses. Nashville was given time to grow into a market and has shown itself to be a fine market for the NHL to be in.