Cornell did a study awhile back that found that employees with their own private offices collaborate less often with their colleagues. A lot less. In fact their very perception of what constituted "frequent" interaction plummeted from several times a day to a few times a week. And it happened in scheduled meetings whereas it was more ad hoc in an open plan office.
They also noted something very interesting: we tend to prioritize our own personal productivity over team productivity, probably because most of us are compensated and promoted based on personal accomplishments.
You can see why management struggles with balancing these two objectives in space design. I think most of the comments here are very cynical but not very well reasoned. They tend to have not very well thought through conspiracy theories, like architecture firms wanting smaller spaces (what?) or pinning it all on cost cutting. Cost cutting? Businesses pay engineers HUGE salaries; if there was clear evidence that a given office plan was significantly less productive it would logically be a huge waste of money to put their highly paid employees in it.
The reality is there is a balance of individual and team productivity that organizations need to achieve. We have learned a lot about the drawbacks to purely private office layouts (like lower team collaboration and depressingly poor social interaction). We are learning about the drawbacks to purely one big open plan layouts (like noise as it scales beyond a handful). There is no one easy solution.
Source: Organizational Dilemmas and Workplace Solutions ‐ Work Effectiveness, Communication, and Office - Cornell University International Workplace Studies Program https://web.archive.org/web/20140615182702/http://iwsp.human...