I forgot to add that cheap hi-rise are often built to a set building life .... usually 40 years. Canberra has the advantage of not being too salty BUT the earth do move in parts (reactive clay) and major buildings in Civic have indeed been demolished due to shifting.
Actual building life will depend on multiple factors but I wonder if the average mug builder or mug punter really cares about stuff such as footings and floor loads. The current Novotel (once called Jolimont Centre I sort of recall) had huge problems when a filing cabinet repository started to bow the floors.
There are exceptions. Some old Housing and Construction built office structures have a design life of 200 years . You won't find units of the same underlying quality and they won't be fitted out with lifecycle costing considerations either.
