Cities, you just said keyword there cities, you can do it in cities because people want to live in cities. They don't want to live on the outskirts. Most of these offices are not in the city centre because the city centre is a really expensive place to have an office, only massive corporations are based there.

The vast majority of office space is in low rent districts on the periphery of cities. Because no one lives there there's no shops, no leisure centres, no schools, no parks or other green spaces. You can't just convert every building into a housing unit without considering the surrounding environment.

It would be infinitely cheaper to just build homes where you actually want them, than to try and convert a building that was never designed for the task.

I know it's not trendy or hip or exciting to say that, but when you look at the economics it just doesn't make sense outside of some very limited circumstances.