The NHL is a copycat league.
When one franchise is successful, teams will inevitably view them as the “golden standard” for how things should be done. The most obvious example of this is when the LA Kings won two Stanley Cups in three years, many other Western Conference teams tried to bulk up and make sure they were strong enough to play against the Kings in the playoffs. The thing is, that would be a bad strategy six years later.
So things are always changing, with new fads from year to year based on who is the most successful.