I've always been curious about the Pennebaker archive. IIRC he once said of the 1966 Dylan tour of the UK that he'd given the negatives to Dylan and Howard Alk and they'd cut it to pieces for Eat That Document. Then I read somewhere about him saying that he had it all buried in his backyard. Then with no explanation it showed up the the Scorcese documentary about Dylan.
He had a realistic sense of the importance of what he's shot. I remember him once saying that if something interesting was happening he would run off and shoot it whether or not he was making a film on the topic. Now, of course, everything is captured on an iPhone or a security cameral, but Penny was there before it was easy.