My pet theory is that its to do with the rate of new developers to the field. I think the accepted figure is something like "the field doubles every five years"

My pet theory is that its to do with the rate of new developers to the field. I think the accepted figure is something like "the field doubles every five years". To me, this explains things like idea-churn, wheel-reinvention, and "grandpas tools", where you see tried-and-true tools (emacs, in this case) passed by because they lack modern trappings, or because people just never hear about them.