the heyday is over, yes.

But like all these things it has changed.
1) the internet is the biggest collection medium now.
2) define folk. I would bet football songs on the terraces would qualify, though they do have authors and they are documented in fanzines. But it is what folk do, and a lot of them at that. Better they sing than fight.
3) It doesn't have to be song or music, there are plenty things that people do that have sprung-up spontaneously - like blue jacking. The collectors of that are probably the media.