When I look close I discover that those people who tried agile and found it worked either were on a much smaller projects with much simpler problems than large projects have; or they are not telling the full truth about agile. (sometimes both). I'm glad agile works for small projects, but it doesn't scale very well seems clear from all the large projects that have tried it and have gone back in major ways (generally not all the way back). The people who have failed projects still often sing the praises of agile, but we have no idea if the project would have failed if something else had been used.