American pop/rock/indie musicians often start singing fairly evenly (like a folkie), then belt words later in the piece.

This is a bit of a truism; I can think of hundreds of examples - like Stairway to Heaven or The Revealing Science of God - which use musical dynamics to bring off the sort of vinegar strokes you're describing here. However, I don't get the like a folkie bit because you're assuming folkies don't use dynamics.

I therefore recommend you listen to Peter Bellamy who was the Dynamic Master of Traditional Song. Many Traditional Singers made great use of vocal dynamics - check out Davie Stewart, Willie Scott and Phil Tanner. Shirley Collins, on the other hand, sang everything at the same level regardless of being accompanied or unaccompanied - flute organ, medieval fiddle, broken consort or rock group, it's all the same! Otherwise - try talking vocal dymanics with The Watersons, and The Wilsons and Cath Tyler.

Like your other musical pronouncements (fiddles etc.) I fear you haven't done the research to back up your theory - in other words, you put your theory before the facts. Also, with a WAV theory, bitter experience teaches us that what you're actually proposing is a correctness of approach, in which case you're way off, as ever.

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On a seperate note, I was yammering on with Ron Baxter yesterday (who for his protests about being a crap singer employs an astonishing range of dynamic expression in his performances) and was reminded of seeing Anthony Rooley & Emma Kirkby giving a recital of Dowland to an audience of 700 in Durham Town Hall with no PA. Rooley instructed the audience not to applaud in between songs so as not to disturb the dynamic adjustment our ears made to the delicate sound of lute & voice. Once made, of course, the dynamic range of the music is as rich as any other.