[h0l0cube]

Or just tear them down and build something new.

Main issue with office space to apartment conversions is the deep floor plan that makes access to sunlight difficult. Retofitting plumbing and isolated fireproofing probably adds more complexity. In terms of malls though, it's perhaps less of a problem to turn these into low-rise residential.

But at the end of the day, it's just land waiting for re-use. I'd be happy for these spaces to become parkland and forest. Or maybe there will be something in the future that needs a lot of land but benefits being located somewhat closer to populations?