They expanded or moved teams to these new markets, and we're slowly seeing who will last.
This.
Obviously good ownership is important & it's equally obvious the long suffering hockey fans of Atlanta haven't been able to rely on this, but I think that the expansion has overall been met with mixed results. It's not the NHL abandoning Canada (well, some parts of it perhaps) neither is it careful, considered & gradual building of the sport in the southern US.
Careful? Given some of the owners that the BoG has approved in the last 20 years (in "fragile" markets), I think we can say that not everything was done carefully.
Considered? In their rush to get into large markets (for the sake of a TV contract to some extent), were these markets properly considered? As an example, if Atlanta is a fickle sports town which is very much into football, can it sustain a team that's going to take 10 years to really find it's feet? Sure there'll be the die-hards, but will the local media give the new cluib enough attention for it to be self-sustaining financially if it's not a playoff regular? (I'm not talking about every year, but making the playoffs say 3 of 5 years). I don't know the answer to this question, but I'm not sure that it was really asked by the BoG as the league moved into these markets. Some of the more recent expansions/relocations were into markets without a lot of pro sports to complete with (Columbus, San Jose to an extent) but others were into crowded but larger markets where there are more people but also more teams that might already have their attention.
Gradual? In the space of less that 2 decades the NHL moved into Phoenix, Denver, Nashville, Raleigh, Columbus, Atlanta, Tampa Bay, Miami, Dallas & San Jose. I'll leave Anaheim out mainly because the NHL already had a presence in that media market. While some of these have been quite successful (San Jose, Raleigh), others haven't been. It's a big task for a league's established teams to be carrying up to 1/3 of the franchises while they find their feet. As we're seeing now, two of the teams in these markets are basically screwed, and the NHL has expended a lot of energy trying to sort out a mess that might have been avoided had the move into these markets been more gradual. Yes we can talk about crappy ownership until the Nords come home, but that doesn't change the fact that newer markets won't sustain a team that's not performing like an established one will (TML & Edmonton to a lesser extent).
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.
This, also. Climate means hockey is culturally ingrained in certain places, and ignoring that is folly. It's no coincidence that the two countries where Hockey is the dominant sport are both straddling the Arctic circle - in Finland & Canada it's far more likely that a kid will grow up learning to skate on frozen lakes, etc than in (say) Guatemala. So yeah, while the number of hockey players in (say) North Carolina has increased after the Canes moved into town, the % of kids playing will likely never be the same as Manitoba, simply because of the lack of frozen lakes. Hockey no doubt has a place in NC, but kids there just don't have as much access to ice & short of an ice age, that's not changing. Junior numbers aren't everything, but with the numbers of kids that learn to skate young in Canada & Finland, the sport is culturally ingrained in a way it can never be in (say) North Carolina.