Elsewhere, someone suggested that it would be necessary to take the rebuild down to the dirt to handle plumbing and the like for individual units, but I’m not sure I agree.
Generally there is significant excess ceiling height in these commercial spaces, no reason the floor couldn’t be raised throughout the space to accommodate plumbing and the like in a way that’s easily accessible for future maintenance. You still end up with 8’ ceilings (or probably rather more) throughout.
Over the years, I’ve watched a number of retail chains and malls die, sometimes suddenly and sometimes slowly. It’s continuously seemed like a huge waste to me, when conversion to residential space would be relatively easy, relatively affordable, could be funded by local gov or nonprofit, and would make a significant difference in net housing costs in a given area.
When ‘traditional’ residential developers are competing with that, and with the ability to slap down standard-sized (AKA easy) risers/walls/etc. within commercial spaces of defined sizes, a further reduction in local housing costs is likely.