It almost certainly DOES cost quite a bit less if you only include the costs that would have been, in, say, 1950 - and control for actually equivalent stuctures

It almost certainly DOES cost quite a bit less if you only include the costs that would have been, in, say, 1950 - and control for actually equivalent stuctures. Environmental cleanup? Tectonic studies? Worker safety? What are those? Does the 1950s deck even have an elevator? I bet it doesn't have a modern bank of ADA compliant ones, security cameras and lighting throughout, etc, etc, etc. How about lifespan? I'm sure we could thrown up a hunk of concrete and rebar in the middle of nowhere in area with no environmental regs real cheap, especially if only care if it stands until the check clears.