Robin has many-many clever and insightful observations, but I think the history books will only remember him for these unbelievably naive em posts. People of the future will find his idea of an em just as charmingly ridiculous as we see flapping-wing aeroplanes, and they will often quote him for comedic effect. At least that's my hope, because I think he would deserve that for the hubris with which he builds these complex intellectual constructions on quicksand.
More seriously, this whole em series is another sterile example of what I called Individualism Bias at this old thread. Johnicolas' short comment there points to the same direction as Carl's paper, but from a different angle. (I am not an economist, but it seems to me that Robin failed to address Johnicolas's points.)
Robin Hanson has made several recent posts on Overcoming Bias about upload economics. I remain mystified why he doesn't link to or otherwise reference or comment on Carl Shulman's 2010 paper, Whole Brain Emulation and the Evolution of Superorganisms, which mentions many of the same ideas and seems to have taken them to their logical conclusions. I was going to complain again in the comments section over there, but then I noticed that the paper hasn't been posted or discussed here either. So here's the abstract. (See above link for the full paper.)