Dead buildings walking

This is pretty unsettling, Seattle's 100 to 150 year old or so year old brick buildings being demolished slow motion by a tunneling project.

That's a shame. Urban renewal on steroids. I don't see how those buildings are saved, but perhaps I'm wrong. I don't consider this to be as difficult a question as zoning policy, but it's close, when to demolish the old and bring in the new--say, Vancouver 1980 and Vancouver 2015.