I am the post's author, and I was referring to a specific building [1]. My understanding is that the owners bought it, unlisted, with the intent to develop it into something else. The City then suddenly made a case for designating it as a heritage property.

This is an area with powerful neighbours who have a lot of time on their hands.

I actually think there's a strong case for preserving this property. I love the look. The architecture is very unusual for Toronto and it looks striking. But, it is always a bummer when you purchase a property with plans to do X, and then get a surprise designation after you pay the money.

[1] https://www.toronto.ca/legdocs/mmis/2018/cc/bgrd/backgroundf...