Ken, I don't trust documentaries: they have the trick of selecting the very best and then making it seem it's the norm. Equally, I've seen a few about snappers whose careers have been in the same time-slot as my own, whose work I've usually admired, and when viewed outwith the pages of a magazine or whatever, the magic simply fades away to nothing.
Photographs outwith their intended context can be quite disappointing.
Partly, the problem with bios about snappers is that, usually, they have not a lot to say. It's not that they find themselves tongue-tied, but that their own lives aren't really what the work is about, and when the genre, style and/or content is what grabs you, it becomes a bit flattening to learn that the people themselves live ordinary, dullish lives as pretty much everyone else seems to live them outwith the job.
But when the work, too, is dull... then there's always a curator to liven up the perception, I guess.