What rituals? Extreme Programming and Lean are inspect-and-adapt processes. You might start with something out of the book, but then you are supposed to tweak relentlessly. If you are doing it in a ritualistic fashion, you're already doing it wrong.

The client never cares about what methods you use. That doesn't mean you shouldn't use any methods.

I agree that experimenting is dangerous: any powerful tool is dangerous. But it has worked for too many people to call it a delusion.

Regarding "couldn't fathom", I'm glad to substitute "didn't fathom". But you certainly didn't understand them, and many other people did.