I think the proper term for metal is "degrading" not rotting. Metal is equally affected by the elements as wood is. Rust = rot, and the cement hooks loosen as the cement also "degrades". Everything breaks down when exposed to the elements, including metals, some metals break down more slowly, but still break down. Take that convo further another time with manmade housing, it is still the same. It still breaks down, sometimes more slowly than others, but breaks down....
I live in an older City too, older than NY, and it has become a bit of a college City recently, only the slumlords don't care or keep up. We have had many accidents here in recent years b/c of apartment building balconies. Some just fall completely through. Metal or wood. Somehow this slumlords never end up paying for it. A clause says they bought it when it was already gone bad, not the right terminology, and the slumlords have owned the properties longer than this young lady lived. I guess no one pushes it and the City concedes to the money coming in from slumlords filing suit against renters not paying. I have no idea.
Very, very sad indeed. I hope someone pursues in this matter.