I'm not sure what you mean. Tampa's about to undergo a major facelift. Pittsburgh looks completely different every year. LA's been there. Chicago is currently deciding if they should continue retooling or do a firesale. Columbus is in a weird no man's land. Not to mention Minnesota, Florida, Montreal.
St. Louis was also inches away from blowing it up
Tampa has been to the finals twice with this core now, and between then and now they've had to cut guys out of their core. They haven't been able to hold on to guys like Stralman, Bishop and J.T. Miller. Stralman and Bishop in particular were huge parts of the team in 2015. Other complementary pieces they had to sacrifice, too. The fact that they weren't able to keep the team together fully did not mean they had to rebuild. They went on to win a Cup.
Pittsburgh went for a big run in 2013, the year they acquired Iggy and other veterans. It was an all-in year, and their inability to win that year made it seem like they were heading in a rough direction. Much of that team was unable to be kept together. It did not necessitate a rebuild, and they went on to win two more Cups.
Washington were a dominant team, and the year before they won the Cup was the year they needed to really make sacrifices and cut guys off from their core. It did not necessitate a rebuild. They then won the Cup.
Boston reached a point post-2011 when they weren't able to keep their core together. They had to get rid of guys. It did not necessitate a rebuild, and they ended up being a Cup contender before too long.
St. Louis last did a rebuild over a decade ago. Since then, they haven't been able to keep a consistent core together. This did not necessitate a rebuild. They went on to win a Cup.
Chicago and LA both did very well within their windows, but made some bad decisions and handed out contracts to reward past performance instead of paying for the future. That said, Chicago may recover from this provided they keep feeding talented young players into the NHL.
I think that based on the evidence, suggesting that the Flames, with most of their core in their mid-20s, is 2-3 years away from playing meaningless, rebuilding hockey, is laughable. The statement that they may have to lose some guys from the core in a few years is perfectly valid. The statement that they are headed for a rebuild is absurd.