What? There is no such thing, WFH employees are more productive without interruption.
The amount of times I had to hold a fart in, struggle to pick my nose, or put on loud earphones just to focus in an open plan office is unacceptable.
Sometimes I want to work elsewhere, and will go to the park or just sit in a parking lot somewhere.
The only benefit I see to physical proximity is the unexpected encounters that can help resolve business situations or help ideas flourish.