Curiously, in my experience it's been senior management (including CEOs) who've fought for open plan offices in the first place. Cost benefits aside, they do wax lyrical about all the reason why open plan is great.
Quite.
They get bonuses because they "saved" the companies millions by cramming more workers in a smaller space. Then they get another bonus to figure out how to cram more workers in, because for some weird reason productivity has gone downhill.