They're all trash. This ultimately comes from web development where requirements are not written down. It doesn't work for developing an OS which is built on requirements gathering at a long duration software life cycle. The unfortunate aspect is that given the volume of web development relative to other software being written, non-web development software product life cycles get drowned in the noise. Doesn't stop agile and its variations being trash.
I'm going to have to very very strongly disagree with you there.
The basic concepts of Agile predates web development, going back the the early 70s.
Scrum certainly predates the birth of the big bang on the Internet, being introduced in the mid 1980s.
I myself have been involved in Waterfall, Agile and even PRINCE2 (when working for the British Army).
Any Watetfall project has always gone totally ass over head and been an unmitigated disaster.
PRINCE2 was so loaded with documentation requirements that I was writing recommendation documents long long after we'd brought the hardware I was recommending. As a resul the project ended up millions of £ over budget and 3 years late.
The only successful projects I have worked on have been the ones using a version of agile. There are thousands of people out there who have also worked on very successful agile based projects.
However, as I said before, when there's no buy in from the business, it can go pear shaped real fast.
I can only guess you have never been on a successful Agile project.
We spent 2.5 years trying to do a combined SAP & Hybris migration before we threw in the towel having poured several $m down the hole.
We regrouped, replanned and then started again, almost from scratch with SAP and a different eComn solution.
And Agile.
We went live just 6 months later.
Are there bugs? Damn right there are. However we're now triaging them and working on them in a methodical fashion.
And this was without complete buy in from the business.
If you want an agile project to fail, you can make that happen quite easily.