“We seldomely find ‘wrong’ in the Rishonim or Acharonim, even in the face of alot of proof.”
True. But sometimes we do. Ibn Ezra famously got some geography in Eretz Yisrael wrong. We don’t rely on Rambam’s medical writings, nor his astronomy. (He would not have wanted us to!)
That they got some facts wrong, however, does nothing to detract from either their greatness in Torah or their authority in halachah! The abovereferenced yud that isn’t missing has no halachic consequences, and neither does the question of Rivkah’s age, but sometimes the differences found in different manuscripts does.
“When Rishonim argue on Rashi they don’t say he is wrong”
Actually, sometimes they do!