In the case of the Starks, the only example that I can think of is the story that the Wildlings tell of Bael the Bard and Brandon the Daughterless. However, I was under the impression that everyone who might know the truth of that tale- Jon Snow, Mance Raydar, Tormund (sp?) Father of Bears, even Ygritte (sp?) who tells the tale- all disbelieve it, or at least strongly suggest that it is untrue. Then of course, there is the issue of consistency- the Starks are referred to as "lords" in the tale, meaning it must be sometime after Aegon's Conquest, yet I really cannot see the Targaryens looking kindly on anyone that flayed on of their great vassals. Further, it is stated that the Starks made sure the Boltons stopped flaying people after they bent the knee all of those millennia ago- I can't see the Starks letting it go either.
I don't think it's ever officially stated anywhere, no. The problem is that the Starks, like everyone else, are given an implausible history that is inconsistent with the events of the books.
In the real world, the longest continually-serving royal family is probably the Japanese Imperial Family, which has reigned continuously for at least 1500 years (with an additional, disputed 1000 years before that), who have achieved that success almost entirely by fobbing off all actual power and authority onto a different hereditary title and letting the nobility fight over
that instead. The Starks, by contrast, are claimed to have ruled the North continuously for
8000 years. The same Starks who have been all-but-annihilated in the past twenty tears of the books' time frame.
To be totally honest, I find it
highly unlikely that Eddard Stark is actually a direct patrilineal descendant of Bran the Builder. Even if you account for the idea that those 8000 years are an inflated figure, that's simply too long for a royal family that is actually out ruling to last.
Getting to the point made by the OP: Prior to the War of the Usurper, Westeros's history is oddly static, especially when compared to the events of the books, an example of what I like to call "New Republic Syndrome", a common condition in works of fiction where the pace of the setting's history seems to undergo a massive, permanent change right around the time when the plot starts, going from a relatively stable place with the occasional threat to the status quo to perpetual chaos where you're lucky if your new world order gets five years before the next sequel.
Or, in short, we're faced with a choice: do we make gameplay that reflects the intrigue and tension of the books, where the past twenty years alone have seen a change in royal dynasty and the deposition of two regional ruling houses? Or with gameplay that reflects the relative stability of historical Westeros, where the previous royal dynasty lasted for three hundred years, and one of those regional ruling houses lasted for
8000? The two are incompatible, and we go with the one that makes for fun gameplay.