If you look for root causes of the Flash failure, I think they go back many years to a fundamental misreading of the mobile market, and to short-term revenue goals that were more important than long-term strategy at both Macromedia and Adobe. In other words, Flash didn't just die. It was managed into oblivion.
Michael Mace has written an insightful history of Flash, and what led to its downfall:
Posted by David Chen Saturday, November 12, 2011 9:53 AM