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

I would argue that both images have their drawbacks and are equally an “after thought”. The railing doesn’t protect / secure the average visitor while the glass doesn’t provide fall protection / awareness to workers outside its perimeter.