Yabia, I agree in general, but more likely Ashkenazim descend from a small group of people, so their mesorah is simply is not representative of the broader tradition. Then, from times of haskala, we started relying on printed and, recently, on Roshei yeshivos to enforce uniformity at further loss of diversity of mesorahs.
Sfaradim (a loose term that usually includes everyone else) are not one mesora, they are multiple mesorahs, probably almost as different from each other as they are from Ashkenazim.