>"but are we losing some fundamental part of teamwork by leaving the office? And does it really just make us more expendable?"

I do not believe I am special in any way but I am remote since 2000 and while working with the clients I often work with teams. At no point I felt like I am loosing some "fundamental part". Maybe because work team is work team and nothing more. I do not consider work as a source of friends even though I have acquired couple this way. Mostly I have friends outside of work.