I've found a direct correlation that the more closely a workplace conformed to the Agile manifesto, the better it was to work in. It absolutely does work in practice, and where it doesn't work I have always found specific, actionable places where they were doing it wrong. At some point you do have to actually spend 5 minutes to try to understand and follow the methodology - I don't think there's any methodology that claims you can ignore everything it tells you, do the oppsite of what it says half the time, and it will still improve your organisation.
(Unfortunately I haven't found any correlation between how much an employer talks about Agile and how closely they actually follow it)