i think you're onto something
people don't care about authenticity in the sense of a persona being grounded in some reality of the self or how it correlates with social background or any of those metrics of credibility / cred
it's about the convincingness of the persona in that performance situation - making people believe that you believe
(Bruza's "Not Convinced" is about this, the failure of the junior aspiring MC who's being dressed down isn't because he lacks for street cred, but because he doesn't put across the gestures of street knowledge, etc with sufficient skill to conjure authority and realness)
that is a generalised thing in pop music and has been for a while - identity as something you can chop and change - whereas once it was an unusual, noteworthy, self-conscious strategy (Bowie etc), worthy of commentary, and something that was deeply divisive
today it is assumed that the persona presented to the public is malleable, swappable - that it'll change, be discarded, etc as part of a career strategy
nobody expects integrity or consistency
but equally i think you're right that they don't want a sense of inverted commas/quote marks or ironically distancing, they want a performer to be fully vested in the role of the moment -- someone like Robbie Willams rolling his eyes as he sings a passionate song as if mocking the whole enterprise, that wouldn't play. Or the Darkness with the singer dude going 'geeetar' just before the guitar solo
questions:
what, besides the Internet, is behind this shift? *
is it a good thing?
* i think in politics it has become normalised that politicians say one thing to one audience, another thing to another audience. pundits talk about optics, about telling a story, about candidates needing a good narrative -- basically an acceptance of the idea of the constructedness of public persona