What's funny to me is, the agile approach seems like it's a much better fit for open-source, non-commercial software development.
The corporate world and is management practices based around quarters and deadlines can't seem to see how anything could get done without deadlines, but that's usually less of a factor with open-source. People laugh at "scrum masters" because in a corporate environment, all the scrum stuff tends to be mostly performative. But it seems to me that open-source projects with multiple contributors already kind of work in an agile manner.
Any diet that has you eating the same thing all the time is gonna have some inherent problems. Your body's needs for various nutrients varies over time, and no "monodiet" will contain all the nutrients you need, in exactly the amounts you need them.
At least, having a varied diet increases your chances of getting everything you need, though that is more likely to see you eating more than you need. There is no perfect solution.