I mean, think about the layout of the average office space: hundreds of small rooms with big open spaces in the center and large, common bathrooms. The plumbing is the biggest problem to fix, because all of it is buried in walls and extremely difficult to retrofit for individual kitchen + bathrooms space.
I guess I'm no civil engineer/architect but I would have thought you could simply tear down all the interior bits and be left with the concrete and steel and just rebuild the layout and attach the plumbing/electrical to the main lines/conduits for those purposes?
But yeah maybe the spec of an office floor of people shitting and cooking is a lot different than a floor of residential homes?
There's also different building code for residential vs commercial buildings. Things like fire suppression systems and stuff. Regardless, it's not that it isn't possible at all, it's that it's prohibitively expensive in a lot of cases.