I know one company that was still "supporting" their application running against SQL2005 until it was kindly pointed out that Microsoft had stopped supporting any & all issue with it. Now they "supporting" their application against SQL2008 , ho hum.

To some extend isn't the industry going the other way as well. How many new languages & frameworks are being used year (and how many don't make it to market or drop into extinction). So instead of being concerned about keeping the skillset relevant for supporting old/legacy systems we now have to be aware of the all there new ways of doing things.