These places have slab floors, and jackhammering sucks, but that isn't the end of the discussion. They typically have really high ceilings, so false floors aren't impossible. Clever architecting can group plumbing-required rooms together. Also, if we're talking about low-income, alternative housing for singles and couples, is a janitor-included shared bathroom down the hall even a problem? Many of the old hotels that are used for this purpose also have this.
Lack of opening windows is a bigger deal. Replacing all the curtain walls and stripping the place down to concrete gets suspiciously close to new construction costs. The land had better be worth it.
I've seen in down quite successfully in dense urban locations for condos but that only worked because the land was highly valuable and the building had grandfathered exemption from zoning / sightline laws for height.
