Missme, seems like you read only half of my post (or pretended to). The Tur at the begining of Hilchos Rosh Hashana says that one should shave before Rosh Hashana. Many Poskim use this Tur to permit shaving.
As to Roshei Yeshivos, many Yeshivos (in the United States) DEMAND that the Bocherim shave, so your theory isn’t correct.