As someone who was also saved from hanging around street corners Jim is clearly correct - although some things discovered in the last few years show there are still some gems out there.

I know of two people currently working with "undiscovered" singers.

However that was not my point - Sharp et al. from that age had an idea of what they wanted to collect and tended to dismiss the rest.

Nowadays we look more at context then they ever did - or at least I hope we do.