What are you talking about? In the flat-managed places I've worked in, a group a peers periodically voted on everyone else's performance. If you had to leave the office for something, you announced it (but never asked permission for it ) on the group mailing list.
> Does somebody extract the excess value from the of the labor you provide, and claim the right to do so by more efficiently organizing the workplace so as to produce value most efficiently?
The one I'm talking about was a publicly traded company, so no. The technical "owner" of the company had little to no say in the management. Maybe this place was not the typical employer. It was in a field where talent is extremely valued. The employees ruled.
If you ask me, it's quite a bit harder to brown-nose 20 of your peers, than just one boss. The dynamics were vastly different than a non-flat, 1-boss system.