[VancouverMan]

The existence of heritage designations and the related restrictions also encourage developers to completely tear down any existing, older, undesignated buildings on their properties as soon as they acquire them, even if the buildings are still usable, and the new developments may be years away.

The developers don't want to risk the buildings being designated, or even just the designation process itself being used to introduce lengthy delays and extra costs, at some point in the future.

Rather than helping to preserve older buildings, the risk of a heritage designation just speeds up the destruction of them. In the end, there are fewer older buildings, and more empty lots.

[supertrope]

Just like how the Endangered Species Act creates a perverse incentive not to report any Bald Eagle nests or even drive off any special animals. Also a rent control law that caps increases to CPI +2% results in landlords taking the maximum increase every year in response to the loss of optionality.