Why do buildings (sometimes) not include seemingly obvious safety measures from initial design?

Question

I’m often struck by buildings with safety measures that have clearly been added on later, e.g., railings, fences, etc. Like this view from a proposed observation deck on the Chrysler building: https://cdn.vox-cdn.com/uploads/chorus_asset/file/19989364/Screen_Shot_2020_05_20_at_11.07.25_AM.png (from https://ny.curbed.com/2020/5/20/21264740/chrysler-building-new-observation-deck)

Even the original railing itself looks like it was an afterthought. Why would the original designer think that a knee-height wall was a sufficient safety measure for a terrace?

In: 15

Answer 1

There may be many reasons. My guess is that the original design did not include any observation deck but the space was only intended for service personel. The knee height wall is there for water management and to hide some of the equipment on the roof from view. Workers would have to be teathered to work in the area and trained to work at heights.