Quote Originally Posted by TheMightyMollusk View Post
The same reason we don't have access to hair like Raubahn, Nanamo, Kan-e Senna, Hilda, Hien, Yotsuyu, Emet-Selch, Hythlodaeus, or plenty of other NPCs?
All of those characters are the equivalent in terms of importance as the likes of Y'shtola and Lyse who do have their hairstyles available in-game. As well as their outfits too in some cases.

They've already made concessions and added some so they might as well go all the way. I've personally wanted Hien's hairstyle and stubble as a customisation option for a while now and have voiced as much many times in the past.