There's nothing wrong with reinforced concrete, but the incentives to produce long lasting buildings are not there. The cheapest bidder will generally win and their building will last the "design life" of the building, but often not much more. The simplest way to change this is to extend the design life, which would result in stainless steels or another more expensive material being used in this application.
What hubris for a landowner to assume there will be a need for a building 1000 years hence.
Buildings aren’t usually demolished and replaced because they are dilapidated; rather, it’s because the new owner has a different need (and a different aesthetic.)
A building that takes 1000 to crumble is just as a much a blight — maybe more — as a plastic bottle that takes 10,000 years to crumble.