Because one wants to have private in person communication. In my experience cubical and closed door office environments maximize communication and collaboration while open concept reduce it.
Closed doors are like therapist room - you get to the meaning of topics fast. They allow conflict resolution and discussion.
Open concept are like libraries, everyone is silently trying to to disturb each other working. Full of visual and audible distractions.
WFH remote meeting have the lowest form of communication bandwidth. It's hard to arbitrage interactions with no visual cues, invites multi-tasking during meetings, and encourages disengagement.