"Their motivation is almost always self-agrandisment."
I agree with most of what you say Paul, but I think it's slightly more complicated than that.
A parallel - here in Ireland there has been a surge of interest in Irish language 'Sean Nós' (old style) songs.
The recorded repertoire from the Tradition covers the whole gamut of styles and and approaches, yet the current singers take them very slow and highly ornamented to a stunning level of ability.
Somewhere along the way it seems to have been decided that this is 'sean nós' style; very beautiful to listen to, but after a few songs all with this delivery it's rather like wading through a field of treacle. Style rather than content.
In the same way I think there is a tendency to lean on a mythical ballad 'style'.
Jim Carroll