I don't think I am. I think even the most casual fans understand that players careers don't last forever. Magic Johnson was replaced by Kobe who in turn was replaced by Ball. This is the natural order of things and fans understand that. I'm not saying that fans don't sometimes yearn for the stars of yesteryear, but as long as an organization keeps fielding exciting talent, people will remain interested. If they don't, I'd suggest that they were never really fans of the sport in the first place and were more interested in the players as individuals.
One of the best teams in the league anymore? They didn't make the playoffs more 20+ consecutive years! Of course fan support is going to wane at that point. You honestly think that if some of those teams with talented players from the early aughts had made the playoffs that fans wouldn't have turned out because they longed for a return of the players from the early nineties? I don't buy that for a second. I think fans stayed away because the teams were garbage and they didn't want to pay good money to go to the ballpark and watch their team lose all the time.
Ottawa has actually had a decent amount of success in the last ten years, especially relative to other Canadian teams like Edmonton, Toronto and Calgary. They beat Montreal back in 2013 I think and we went on a huge run last year. Yeah, they've missed the playoffs a few times in that span but such is life in the new NHL designed to create parity. Teams can be in one year and out the next. Only the absolute cream of the crop like Chicago, Pittsburgh and Washington seem to make it every year. Most people seem to think of Tampa as the new challenger for king of the Eastern Conference but they've missed the playoffs 3 out of the last 6 years.
Again, that's not the point. The point is casual fans lose interest when the players they use to follow are no longer there. Fan support isn't a linear continuum where support is sustained continuously. It has an ebb and flow and is affected by team performance, player arrivals, player departures, player performance, environmental factors, etc. Magic Johnson to Kobe is certainly not an example to be extrapolated, Kobe was literally the face of basketball for most of the early 2000s. You're acting as if most fans are like you. They're not. Most fans of a team don't watch every game, they can't name all their players, they don't actively follow the teams every move. If a team is "meh", and the stars you use to be able to name are gone/washed up, you might care less. That doesn't make them less of a fan, it makes them a casual fan.
Once more, you're not getting the Blue Jays example. The Jays attendance/support faltered long before they had missed the playoffs for 20 years. In fact, Jays support and fan awareness of the team was down significantly even five years from the team winning their second consecutive World Series. Jay's fan support began to fall almost immediately after their poor showing in the 1994 season, a
year after they won their second straight title. In 2-3 seasons after the World Series, there was almost no big name star left from their late-1980s early 1990s heyday. Despite picking up huge stars like Roger Clemens, Carlos Delgado, Roy Halladay, in the late 1990s and early 2000s, the team couldn't bring back their luster. I believe this can be extrapolated on a smaller scale to the Senators. People didn't long for a return of the players from the 1990s, but they associated a team they wanted to watch with those guys, and unless the Jays were doing something exciting, they didn't have that attachment anymore.
No, the Senators support hasn't plummeted in the decade since they went to the Cup Finals, but it wasn't as high as the Jays were in 1993 either (the Jays were the biggest team in baseball, by far, in the early 1990s). Combined with the fact they've had really no shot at competing since the second lockout, and the decline and departure of their earlier stars, fans aren't as engaged with the team. Karlsson is a superstar, he's electric, and he's fun to watch. But what else about the team is exciting? For invested fans, lots probably. But for casual fans? I doubt many casual fans expected the team to go to the Conference Finals, and fewer still that they had any chance at a cup. The team doesn't have to consistently miss the playoffs to lose fan interest. Ottawa has been one of the most successful teams in Canada since the 2005 lockout, if making playoffs is your metric of success. But they haven't been legitimate contenders for a long time. They've been "meh". Not horrible, not a disaster. Just "meh". And in the National Hockey League, being average is worse than being terrible. Part of the problem is a marketing issue. Melnyk hasn't done much. But it's clear the same fervour that existed in the years subsequent to 2007 isn't there anymore.