Not sure about Adobe having reached a new stage with the release of AIR. It could be a significant date but this can only be clear later. I have found some evidence that Postscript is not promoted that often. The webpage still refers to Acrobat 6 so may not have been changed that often. The industry quotes about the PDF Print Engine are from 2006, maybe around the time of IPEX. There could well be an update during drupa but my impression is that most of the time this phase is more or less over.