So how does open demo-ing a concrete building work then? Last I heard reinforced concrete was harder than ice. Not that I want to see public funds spent on breaking it up, when the sun will do the job for free if we wait, but this isn't something that construction equipment couldn't handle.

Concrete buildings aren't solid concrete. There are still a few WW2 bunkers around these parts, because it's almost impossible to demolish them, by design. And even those aren't solid concrete by any stretch.