But they’d have had actual, physically present mentors too, wouldn’t they? (Art school teachers, bohemians, Korner, Mayall.)

In any event, whatever you mean, I’d say that facility is never there by birthright, isn’t to the manner born, even if some people obviously can have a leg up regarding what they were born to and weaned on. But once you’ve got the facility, it’s yours.

“placed far more uncritical trust in borrowed systems of words” Hmmm. As someone halfway between Green’s generation and yours, hmmm. I don’t know. But what you seem to be saying, when you say “uncritical trust,” is that the facility in using the terms to, like, say something was never attained. That’s probably not what you mean, but does seem to be what the sentence implies. Of course, I’m placing something pejorative into my reading of “uncritical trust.”

Barely know the Green-era FM, and haven’t (yet?) watched the doc. Is it crucial for me to see?

I doubt very much that the Stones, or Dylan, or the Yardbirds, or the Kinks, or Hendrix, placed uncritical trust in their music. Otherwise they wouldn’t have been constantly reshaping it.