Somehow, and I don't know how this is still possible in 2013, but I don't consider remote collaboration tools to be a "solved" problem. I say this because at our shop, we have blocking issues with remote conferencing on a pretty regular basis. The most common problem is when one person turns on their speaker and creates feedback/echo, and then we have to spend an annoying 5 minutes just tracking it down. Maybe we're on the wrong tech (we use WebEx and Lync), or maybe it's a training problem. But I suspect we're not alone..

If there actually was a seamless audio/video conferencing technology that still worked perfectly even when subjected to the dumbness of office people, then I think I would have a different opinion of remote work.

But as it is, I think the productivity tax is significant enough to be worth worrying about. Especially since the tax is not just inflicted on the people working remotely, but also on everyone in the office that interacts with them.