Interesting points, Chris. I suppose I linked concentration to productivity in my post because I find that the two are related in some complicated ways. Yes, if you don't concentrate (because you lack the discipline or the software and hardware setup makes it easy to be distracted), your productivity will suffer. However, in my example I was talking about the opposite experience: I hit the wall productivity-wise and couldn't find a way of moving ahead, therefore I was more likely to be distracted and lose my concentration (as that was less painful).

But I'm all for software offering distraction-free environment options (such as the excellent full-screen view in Scrivener) or easy hoisting in Bonsai.