Converting office space to living space strains infrastructure in ways not intended by the original intent of the buildings. They can’t put thirty apartments on a single floor of a high rise and have those residents use the same four bathrooms per floor that the offices had. Same with sewage. Same with electrical.
Water and sewage is a real question, that’s true. From the projects like this that I’m aware of, fire safety is actually the bigger issue, though. Usually sleeping areas are required to have an easier escape route than would be typical in the middle of a big office building. I guess you can add pipes and pumps without too much modification, and offices use plenty of electricity, although probably not in the same pattern.
As for the systemic issues, governments do manage to get things done sometimes. The exact details of such a legislation are more granular than I really would want to hammer out on Lemmy.