I think the methodologies are fads and nothing more. I think the diminish productivity in everyone.
I do understand that some people need more structure than others but I also think that the short “sprints” serve only as an excuse to keep up the pressure so people work 60–80 hour weeks. Nobody is every caught up working 40-hour weeks.
All the methodologies entail extra meetings, which is to say, extra interruptions. Interruptions that break concentration, and concentration is the foundation of good software development.
Their phoniness is beautifully illustrated by the goofy nomenclature they bring with them; refactor, technical debt, stories. None of these have precise meanings and all of them replace more accurate words for the same thing. Because the methodologies really don’t add much, if anything, so they bring in new terminology to manufacture an appearance of something new, sort of like Microsoft moving the icons around and releasing a “new” version of Office.