There are a few things coming into play here that have wreaked havoc on NHL franchises:
1. With its strong push for national television revenue that began in the 1990s, the NHL made a decision that effectively put a higher value on large cities with few hockey fans over small cities with many hockey fans. The relocation of the original Winnipeg Jets to Phoenix was a perfect example of this. Winnipeg had about 400,000 hardcore hockey fans among about 600,000 people at the time -- but Phoenix was considered a better NHL market because it had about 4 million people, even if hardly any of them were hockey fans.
2. There are many smaller cities that might be great hockey markets, but the NHL has simply priced many fans out of the game. This is why teams from large cities with a lot of corporate support have the most traction in the NHL, because that type of support doesn't get priced out as easily.
3. As strange as this may sound, some metro areas have enormous fan bases but aren't very strong NHL markets. This is because these places simply have too many other less expensive options for hockey fans. The Twin Cities of Minnesota is a perfect case in point. That may be the best hockey market in the world, but they lost the North Stars to Dallas back in the 1990s because they didn't have the support of fans who didn't want to pay NHL prices when they could attend NCAA games, high school games, and even children's games for a lot less money. The Minnesota state high school hockey tournament will often attract 18,000 fans to the Exel Center in St. Paul for days at a time every March, but when the North Stars were there they didn't have a strong fan base at all.
I don’t think the “original six” are immune to losing . Toronto lost their sellout streak a couple years before Matthews was drafted. Chicago couldn’t draw flies during the last years of “Dollar Bill” Wirtz’s ownership. Even Detroit while winning had plenty of tickets available during the last Stanley Cup runs.
The other points are about the NHL being a business. The percentage of hockey fans is only part of the big picture and apparently not enough to make the business viable. That means they want corporate support and the high prices they can pay and a population high enough to have people pay season ticket prices . If the population doesn’t want to pay, it isn’t an NHL hockey market.
After all star players are rightfully well paid, the cost to run a winning franchise is high. Also the value of the Canadian dollar plays a huge roll in the viability of markets up north. The pay is in US dollars (or indexed to) even in Canada.
For those who don’t want to pay NHL prices, there’s juniors, the AHL, the ECHL, college and high school. I’m lucky I live in an area near all those. There is also free. Hockey players practice and scrimmage in the summers.