Maybe my memory is fuzzy, but wasn't there also some sort of major alteration that was going to be needed for stairwells in the building for it to ever be used again? I may be mixing up two different buildings.
Makes me wonder if it's a fault of 1980's postmodernist-style skyscrapers that they're just not amenable to change-of-use. Were their architects so shortsighted that they couldn't imagine the buildings becoming obsolete for office use, and then facing conversion to another use, or implosion? What design changes, if any, would have saved Landmark Tower from implosion in favor of residential conversion?
Not to split hairs, but there was nothing 1980s postmodern about Landmark. It was completed as it stood when demolished in the late 50s, but I get the point you're making.