Or not doing it properly. And I understand the suspicion, I really do; but in hindsight, if you honestly tried to review how an organisation was operating, would you sincerely be able to say that it was adhering to a certain agile methodology/framework/mindset/strategy/whatever?
I have so far not see an organisation that would be following scrum, as it is described in the scrum guide; or kanban, as it is described in the kanban guide. I have seen or heard about various organisations that use these words, but they have little resemblance to what was actually proposed. So I can't really say if agile (or any of its particular variants) work or not. I have not seen honest experiments properly run.