"You seem to be treating folk as a genre, which it is not"

I am indeed treating folk as a genre. For me, it very much is. That is the best way for me to define the music that I like and make.

"Matt - I don't think any folksingers called themselves "folksingers" until musicologists did."

I totally agree with that. It could be said that that is when folk became a genre.

"I think a distinction can be made, though a flimsy one, as good as any other flimsy definition of folk - to make folk music in the living room (like Daniel Johnston did in the late 70's and early 80's) and to do it yourself with the most limited supply of resources is quite exceptional."

Yes, you could use that as a definition, but it is not much use in describing the music that I listen to and make. It is also not much use in describing the music that most people who call themselves folk musicians make. It is also not much use in describing the CDs in the folk section of record stores, or on Spotify, or sang in folk clubs, or performed at folk festivals.

It's a definition that applies as much to Billie Eilish (that's how she started) or Jpegmafia or anyone making techno or drum'n'bass as it does Daniel Johnston. For that reason it's not a useful definition: it includes far too much music that nobody thinks of as 'folk'.