The rarity of Fenris Hair is unreasonable

So according to wiki we can only find Fenris Hair in frost caves as a loot.
Considering the average amount found in one and how common they are, adding the cost of Fenris armor set it becomes very unlikely to assemble a set in a reasonable time.

I thought Root armor set was hard to farm for, but at the end of the day just running from crypt to crypt I was able to gather enough for lvl 3 full set. I think I was upgraded before my mate who was going for Iron armor.

Now, it's totally different with Fenris. Last frost cave we visited yielded TWO pieces of Fenris hair total.

Wouldn't it be more logical if it dropped from Cultists and Fenrings?
Those are also quite rare monsters but at least I could go in the mountain during the night and slowly grind my way to the set instead of just hoping that the next Frost Cave is just behind the corner and that it has enough hair.