my experience with online friendships is that it's much easier to self-select. you absolutely can get to know people really well over the internet, but it's also much easier to completely ignore who seems a bit annoying. at least for me, gathering people in the same room and forcing some physical interaction is more likely to make me get to know the people i probably wouldn't otherwise.

that being said, i think the whole productivity aspect is bunk and bosses want you in the office so they can say the things to you that they're afraid to put into writing. "in person collaboration" isn't code for you talking to your colleague, it's code for bosses want to be able to catch employees in the hallways and ask them to work on pet projects that are outside the employees designated duties or priorities, without a meeting record.