Many buildings in Venice are hundreds of years old. If the cycle involves replacing, say, 1% of buildings every 5 years then that isn't necessarily in conflict.

Many buildings in Venice are hundreds of years old. If the cycle involves replacing, say, 1% of buildings every 5 years then that isn't necessarily in conflict. Most of the buildings would be hundreds of years old, but after 50 years of an effective moratorium, 10% would need to be replaced despite the fact that most buildings are hundreds of years old and don't need to be replaced. That's a little different from saying the entire city needs to be rebuilt, but it will eventually.