don't get me wrong agile is an improvement in the sense that iterating on small deliverables is better than a single giant waterfall process, no disagreement there
but yeah if your tool never delivers in the alleged benefits, ever, anywhere, then it's not good enough to say the problem is the people
tools are welded by people
if your tool doesn't take that into account and assumes and requires its users to be perfect, well, then it's not a very good tool