I seem to remember 2E being moribund when 3E was released and everyone eager for something new just cautious that 3E wouldn't be Dungeons and Dragons.
With 4E, 3.5 was actively played and supported and there was no need among the players for a new edition.
Just want to step out of the Plane of Shadows for a moment to say how much I enjoy this Story Hour. Planecape was a setting with great potential and it is always interesting to see what directions peoples' campaigns have taken.