Earlier quoted context omitted.
I always thought open offices became popular because it was literally the cheapest set up for facilities. For startups it worked because all you had to buy was desks. Somehow that got spun in to 'open offices are so sexy!' Open offices are horrible for productivity imo. Moved to a job with an office and it is so. much. better.
That's why we have them... we literally can't afford to give everyone (or anyone for that matter) a private office.
A measly additional 60 square feet of floor space, 10-20 grand in construction costs, and the same desk/chairs, amortized over 5 or so years.
Even building separate rooms for groups of programmers would provide for great gains at low costs.