Correct. A civil engineer explained me that once. Up to 100 years ago, engineers made their calculations for the required structural design, and then multiplied them by three, to be sure it would be safe. Sometimes, bridges designed that way, failed to collapse when blown up in wartime.
Today's building design is rather cost effective. The most expensive part, the foundations and basements, are built for durability, but what is erected upon them, is so sharped-edged concerning structural stability, that structural failures are allowed for, say, 15 percent over a designed lifetime (e.g. 30 years). Knowing that each gain of 5 percentpoints doubles the building cost (and for some structures, a higher stability level is required, e.g. nuclear power stations), investors rather prefer to 'postpone' this extra investment for 30 years later, when the old building would be structurally worn out and torn down (apart from the basement and foundations), so they will have a brand new one for the same (inflation corrected) extra budget as would have been needed 30 years earlier for a more structurally durable construction.
Of course, these financial constraints are less a concern, when you can save building costs by having the work done by slaves or serfs.
