Folkie Dave I agree that there has been a concerted rise of instrumental virtuosity in recent years in all forms of music. The jam session may have some bearing. True for jazz, OT, Bluegrass or Irish sesiuns.

As you have mentioned, there are regional exemplars of folk virtuosity in the UK as well as the US.

The notion of "the Tradition" is a fiction as Dick Greenhaus has pointed out. There are "traditions" and they are developed through respect and interest.

Singing in traditional styles has not had the attention. The voice is a flexible but difficult instrument to master. So much depends on the personality of the singer as well as the tonal quality. It is also open to wildly different degrees of interpretation by the audiences.
How else can you explain a Louis Armstrong whose voice sounds like sandpaper but is adorable and loved internationally? And then there's Dylan.

"The tradition" is a mask for the understanding of "traditions" because it makes an assumption that is not correct and that is as an overall blanket for what some feel is
more "authentic" styles of singing then others. It's another label that obscures the meaning of "traditional" usually by self-styled academic types who claim knowledge that
becomes a suit of clothes rather than a closer look at what a tradition is.

Frank