I work with hardware and being able to have someone physically look at a schematic with me or explain something to me in person greatly shortens the amount of time it takes me to understand them.
Edit: I also think we don't know the long term effects being remote has on innovation. It seems like people congregate in cities because the rewards to being near people are greater than the costs. Is technology really so good now that it can offset all the years of evolution we've gone through to make us into the social animals we are?