I think there are problems with modern longevity science. The OP's "A fundamental challenge that longevity gurus face is that what’s true is often boring, and what’s interesting often isn’t true" is plausible.

But it also seems like there's a tendency for debunkers to be too categorical. It should be kept in mind that anyone aged around 110 would have gone through a variety of age and other record systems. Moreover, it's quite possible exercise and special diet as such really really aren't that useful.