I stumbled on this amazing interview from 1995 with Terry Zwigoff, the director of Crumb and Ghost World. Zwigoff is a member of Robert Crumb's band, the Cheap Suit Serenaders, and an obsessive collector of 78 RPM records released before 1933. The focus of this interview is Zwigoff's passion for old-time tunes.
"(Pre-1933) music is more backwoods and I think of it as representing real isolated pockets of eccentricity… I see radio, or mass communications in general, as ruining that isolation, which to me is what's most interesting about it. People started imitating. People could hear Bing Crosby on the radio, so they'd all try to sound like him instead of having enough faith in their own weirdness to keep it going."
Link to Internet Archive of interview page