Well…the ‘why’ is likely to be linked to the ‘when’, and the why is instinctively understood (if not documented) and can probably be summed up as easy access to knowledgeable information. Information that was once obscured in culture and tribal know-how (rarities’, values, memories, anecdotes, places, people, DJ’s, c/u’s, etc). Essentially, underground.
By the way, that knowledge is not, and has never been elitist, but you had to seek it out. In the same way that you would seek out your ancestry by visiting the local authority records office, the library, registrar, parish records, etc. Genealogists were once considered underground, but now we can all be genealogists with internet platforms allowing access to data and knowledge.
So…when did NS surface from being underground. I think, once access to that knowledge was unleashed on the internet to the masses. Clues are everywhere: Discogs launched in 2000. The first YouTube video was April 23rd 2005.The first article I can find on [here] Soul Source is an article dated Sept 1st 1997 (maybe there is an earlier one in an archive).
And so, as web sites and social media has grown, so has access to the vast amount of knowledge. Albeit access is done by some people that only have a self-serving purpose. On the other hand, good new soulies will have access to it also, and that can’t be a bad thing – because they’ll realize what’s been invested emotionally in the legacy for many years by so many people (and to be clear I’m not speaking of myself here, but those that did 100’s of all-nighters, brought back records from the USA, DJ’ed and promoted NS throughout their life, write about artists, labels, records. Many of whom are members here).
As for me, access has been very positive. There’s no way as a returnee I could have ‘picked up the threads’ without it. I’ve heard great records that weren’t played when I left. [It’s been like a blind man having his sight restored]. I can surf venue lists, buy records, bid at auctions, get tickets, discover scarcity & value, belong to community and seek opinion, plus the rest. I cherish the legacy, but given my age, I don’t think I’d be ‘back’ if it was all still ‘underground’.