To compound the issue, I get the feeling the dev team paired the hair and the ears for Viera which isn't the case for Miqo'te, much like how the Hrothgar have their face tied to their hair, now I know that sounds strange but hear me out here, I get the feeling they did this and I feel like the lack of hairs make it obvious they did it this way. If the ears were just part of the model then basically every and any hair would work by just simply clipping through the ears and there'd be no issue, but there clearly is one since it's been a year from launch without ANY of them, also the head items Viera can use? No hats, nothing that changes or alters/swaps the hairstyle.
This means those base hairs you can choose as Viera are all built-in with the ears present, if they were going to add a hairstyle for the Viera with the current aesthetician system it would have to unlock both versions of the hair, ears and without, which they can't do because then Lalas would be running around with Viera ears jutting out. This is also likely why the dev team said previously they were considering options and that they might just release new hairs as race specific things for Viera and Hrothgar, aka let's use Braids, if they released a new Braids hairstyle there'd be 2 versions, one that's for every other race and one specifically for Viera (to add the ears), if Hrothgar got lucky they'd also get one unique to them with a new face (they tied hair and face for Hrothgar).
Further I get the feeling the ears are a base structure and the different choices for lop or fur or whatever is just different details that overlap/overwrite the base ear (much like how wearing high heels doesn't change your height, it just removes a portion of your shin/ankle/leg length).
Could be 100% wrong but that's the vibe I get from this, maybe we'll find out when the race specific hairs manifest from the void.