Just to finish my train of thought: if ice dance does appear to reward seniority in a fairly predictable manner, is it really a sport?
I'm not going to get into the question of what defines a sport.
I do think that we've seen a lot more unpredictable results post-1998 with required elements and required fall deductions, and especially post-new judging system, than used to be the case. And there were occasionally upsets in the older days as well.
Never as much as in freestyle, but then the actual performances in dance don't tend to be a volatile -- most of the elements are such that mistakes don't cancel out all or most of their value the way falling on or popping a jump does. So basic skating skills and presentation, which are more subjectively judged, play a bigger role in the judgments. And those things tend not to change hugely from one performance to another and to improve gradually with experience, until injuries, aging, etc., start to hold the skaters back.
And because so much is dependent on judges' perceptions, and people tend to see what we expect to see, judges would continue to see dance teams as being at a certain level until something obvious gets them to change their perceptions.
Even in the old days, it wasn't totally predictable which teams would move up over time and which wouldn't. New teams on the scene might debut a little lower than experienced teams of the same skill level, or a little higher if they're political support was especially strong, and then they would move up only IF they made visible improvements, or the judges could see that they'd been undermarking them in the past, or teams ahead of them made mistakes or showed visible decline. Especially effective choreography could help, and especially poor choices could hurt. And of course most teams in the beginning or middle of their careers were improving their skating. So getting noticed as improved
With the new system, overall impression is less important than in the old, and the details are more important. So there's less room for preconceptions to overshadow the actual performances.
Beginning ice dance fans might have only 2 or 3 criteria to judge which teams they think are better than the others -- e.g., Do I like the way they moved to the music? Did I notice any visible mistakes? -- and miss some of the more important aspects that are actually being judged.
More experienced fans (or inexperienced judges), especially watching live instead of on TV, can take more kinds of details into account, maybe 5 to 10 on a regular basis. Experienced judges might be considering 20 or more criteria to make their decisions, although each will have their own priorities of which are most important.
Fans will still often disagree with the judges. And with each other. And judges disagree with each other -- the results are the consensus of all their opinions. We can often find at least one judge who agrees with us when we don't like the results, or at least one who disagrees and we can use as a poster child for bad udging even when we do like the results. But on those occasions when all the judges do seem to share the same opinion, chances are it's us who are missing something and not the judges.
And why would people keep watching if they can't expect the best skaters to win?
Perhaps
1) Because they enjoy the intrigue of a contest of politics/perception, real or imagined, as much as they would enjoy a contest of technique. Perhaps more -- it's easier for fans who without much technical training to come up with political explanations than with technical explanations for results they don't agree with, and fun to feel morally superior to the judges.
But more important,
2) Because they enjoy the actual skating for its own sake, apart from what the judges think.