That doesn't really hold water... Medvedeva hasn't lost to anyone outside Russia, and she's 18 years old. You think that the age limit is what prevents the rest of the federations from winning? As I was saying, it's reliant on top talent emerging.
And what do I mean with a transitional period? "Well, the next batch of juniors is better", "well, this girl is better than anyone ever was for this age group", "well, this girl is even better"... This sort of a thing. Constantly there are more and more talented ladies. Of course they would be expected to surpass the older generation. This is a transitional period. So what happens when we have such a good skater that someone younger is no longer "better than anyone ever was at this age"? That's when the possibility for sustained success for a skater arrives. But the issue is the increasing talent level, not some age thing.