In my estimate, you are still way low.
In one environment I spent a number of years in, once work-at-home became more acceptable, almost universally, the most productive people -- by my prior and continuing observation -- pushed to add as much of it to their schedule as they could manage.
Even the real collaboration -- email and instant messaging, first. Phone calls where needed.
Some face-to-face meetings could be plenty productive, when properly defined and run. The far majority were not, however.
The best people hated open space. Those who loved it, you typically had to remind 5 times of everything. Or nag. Increasing your own burden, in the process.