Oh, I didn't think you were saying that, Gaveston.
I think Sondheim's score DEFINITELY embodies that conceit. In fact, the score could almost be a standalone song cycle that nails that. Sondheim subverts basically 100 years of American popular music to get the point across.
But it's Weidman's book that really weakens the piece, as a whole. While Sondheim's score is clearly cohesive, Weidman's book is less so. While the score messes with audience perceptions and juxtaposes popular music with darker themes, Weidman's book is less daring and cohesive. Until you had called the show a vaudeville, I had never really thought of it that way, but it's only sporadically presentational (the Balladeer, typically). The scenes are played straight. And until Mantello made the ghostly carnival midway the unifying location, the piece just sort of took place in a weird metaphysical nebulous... dimension, where time is nonexistent or vague.
"...everyone finally shut up, and the audience could enjoy the beginning of the Anatevka Pogram in peace."