Office building floors are concrete, usually. You cannot dictate where plumbing goes. Drain pipes are ruled by the iron fist of gravity. And down is technically in your downstairs neighbor's space.
But the taller office buildings are much harder to convert, not impossible, and can lead to some stunning excesses (like really high ceilings with horrible heating costs) that wouldn't be possible in a direct for residential build.
> , some of them even make the plumbing added look more of an industrial design
This was probably out of necessity rather than aesthetics, but again, hipsters (especially rich ones) love this stuff.
Skyscrapers are much more difficult to convert (there's an NYT article on it).
Midrise buildings might be the best bet, but even then unless you allow "basically slumlord" conversions, it's probably simpler to knock and rebuild, even if you disguise it by leaving the outer walls up or something.