Are you implying that when people talk about a "loosing culture" that they are saying you can't get out of it? Your statement implies that Edmonton and Buffalo appearing to be good is proof that it doesn't exist. A loosing culture is a thing, its something that athletes talk about all the time and if you are going to cite teams to go against this narrative, I wouldn't mention Edmonton.
When a team perpetually looses, without a doubt a loosing culture is created. When people talk about this, they are not saying that you can't get out of it forever, its just harder. Maybe you have played in the NHL and have a different perspective, and if so please share but I have heard countless athletes talk about this. Keep in mind, this isn't created by a bad season or two, we are talking years and years of loosing, and failing to build.
Sometimes people make this out to be worse then what it is, but a loosing culture is creating an environment where apathy/pessimism is paramount. Player tend to not give 100%, a couple loses make everyone want to give up, media go nuts and rip management/players, players begin to feel alienated etc etc. etc. Yes if you get better players and are able to switch things up you can come out of it, but its just a harder path.