It doesn't meet the requirements of tennogen items, specifically syandana one.

https://www.warframe.com/steamworkshop/help/index.php?page=creating-a-syandana

Attachment point needs to be along the upper spine. Tail Syandanas are not possible, sorry.

and also on the bottom of that page:

Submit with intended default colors, but no gold metals

It's not as simple as just plopping it down on a warframe and calling it a day. There is a reason why all syandanas are attached at the same points.

They would have to revamp all warframe skeletons in order to be able to add tail syandanas, and also they would most probably have to redo every single warframe animation to add that stupid tail attach point. Get over it, it's not going to be added whether you want it or not.