I’m fine with that.

Turn them all into housing we desperately need

“But office building pipes aren’t set up for that!”

Okay so make communal housing/bathrooms for cheaper rent or invest in expanding the plumbing

“But that’s too expensive!”

More expensive than $800 billion??

A bigger problem is the location, office building are not located in residential areas and as such lack a lot of facilities, e.g. no supermarkets and other shops in walking/cycling distance, no MD/pharmacy and other healthcare facilities, no schools or playgrounds, etc. etc.

You could literally add those services inside many of these buildings.

You want to open a entire supermarket for a single building ?

That would only work if you convert an entire commercial district, but then you still have all the other infrastructure problems. If you’re going to do that why not level the entire lot and build proper housing?

It’s very common to have grocery stores in the bottom floors of buildings that are open to everyone, not just the residents of that building. And in parts of Europe it is the norm for large commercial/residential buildings to reserve the bottom floor for small retail businesses. It would greatly improve cities to have this.

I’m in Europe and large office buildings that are empty are usually not the ones with stores on the bottom floors, those offices (and residential buildings) are older, smaller buildings in city centers and are very much in demand. The large empty office buildings are usually in commercial districts on the edge of cities with very little foot traffic. There is no market for convenience stores there if you just convert a single office building.

Say you get 100 apartments out of it, you can’t run a supermarket on 100 customers.

I don’t see why it wouldn’t be a market for all the buildings around it too?