It's possible the owners wouldn't want to start running a renting to tenants business if they were renting office space, since it's less money per client and more maintenance/running costs. The governement could very well be better at handling this than private companies, and would companies would sell for liquidity instead of future profit, and go into something else.
Esit: I'm no expert on housing, but this would disrupt wildly the value of housing in the city, since the benefit of being close to offices vanishes and housing is all over. Profits from exploiting the buildings could very well be less than interesting for private companies.
It could also be governement policy to sell this housing to individuals instead of renting, creating a lot of capital to be used by individuals (since mortgages are tough to reach for most people today, this could be nice economic leverage for individuals, if they could buy cheap housing and mortgage it.
Not sure what that'd do to the economy but I doubt it would be bad.
I garantee you that keeping em empty isn't lucrative, so we gotta do something with them. Housing makes some sense.
What are you suggesting?