[mbg721]

The lower-friction result is that the offices become huge apartment buildings with reverse-commutes to the suburbs, hoping the "stuff to walk to" survives. There are issues with that too, like plumbing and windows.

[red-iron-pine]

most of those issues will be very expensive or insurmountable for most high-rises -- a non-starter

you're basically rebuilding from scratch at that point.

[mbg721]

Maybe this is a US perspective, but those are attractive properties.