Why is the winged helm better than a bronze helm at equal quality? Ore rarity goes iron->tin->copper with iron being the most common and copper typically needing level 3 and below. If you have copper you'll almost certainly have access to the metals needed to make either. It's also often harder to make higher quality bronze because tin ore is usually shallower and lower quality than copper ore. The only reason I can imagine for bronze helms having worse stats is because it's easier to raise leather Q than chicken Q, but the stat difference is enough I'm not sure it matters.
Bronze stuff probably wouldn't be worth making even if copper ore was changed to be common and shallow like heavy earth. Back in W3 we used bronze for months because almost every iron mine was claimed, but with iron as common as it is, I don't see its place anymore. Even a solo hermit with a fulltime job can manage a few steel crucibles if he lights them on the weekend. Where does bronze fit?