What really "killed" Agile are two things: the absence of good guidance on how to apply Agile principles as opposed to canned methodologies, and the fact that most people don't have the skill to apply the principles without guidance.
There is some good guidance it there, but you have to get outside of the Agile "brand" for most of it, since much of the work on evaluating methods and other aspects of higher-level metamethodology that fits in with Agile principles is associated with "Lean" rather than "Agile".
There is some good guidance it there, but you have to get outside of the Agile "brand" for most of it, since much of the work on evaluating methods and other aspects of higher-level metamethodology that fits in with Agile principles is associated with "Lean" rather than "Agile".