I just got confirmation that one of the true reasons was "control", ie. being able to have an eye on every worker. Many managers feel out of touch in the modern workplace, so it's not just employees who are frustrated. The next "fix" in the eternal swing of the pendulum is of course: easier access and overview on workers.

The problem is, nobody else care about your "deep work", or benefit much, except yourself. The pendulum always swings too far, and turn back..