Answer: because the player can forge ridiculously OP gear.
Ebony Helmet of Peerless Archery (Epic)Look Lydia! A strong looking helmet!You'll become even stronger with this!Why doesn't my Thane wear it herself...Fun Skyrim MOD ChapterDwarven Helmet of Archery (Exquisite)Steel Plate Bracers of Sure Grip (Flawless)Nordic Armor of Extreme Health