Before I could rouse myself to write something on this, Amanda Petrusich has done a bang-up job for Salon. Her central claim is that Winehouse's struggle with addiction gave her the sort of credibility to sing the blues that normally wouldn't be open to a young, white, jewish, girl from London:
Addiction is a fundamentally different kind of hardship, but Winehouse’s life wasn’t charmed. She had credibility, suddenly, and that trumped everything else -- race, circumstance, origin. She made dozens of unforgivable professional and personal mistakes, but no one could accuse her of being full of shit.
Read all of Petrusich's piece, I think it gets it exactly right. The only thing I would add is that I wonder to what extent, if any, Winehouse felt obliged to continue to draw from that well of authenticity. That is, I wonder if Winehouse, like others before her, bought into her self-image as a messed-up singer of the blues, which made it that much harder for her to get clean.
I'm not suggesting she was simply playing a role, or that she killed herself in the name of cred, but there is a powerful looping effect in all of our identities. All identities are social constructs which get their power from being recognized by others. As a result, there is a looping effect in our identity construction, where we internalise the norms that govern our chosen (or assigned) identities. When the norms of a given identity contain a built-in mechanism for both radicalisation and self-destruction (as they do for an identity like "messed-up singer of the blues"), it is not hard to see how it could become literally inescapable.
I made a similar argument in my refereeing of the spat between M.I.A. and Lynne Hirschberg, for Mediaite:
The problem is that M.I.A. herself buys into the authenticity hoax. This drives her to counter the charge that she’s a hypocrite or a sellout by ramping up the “political” dimension of her art and her persona – she needs people to see that for all her money and security, she’s still Maya from the ‘hood. And so we get her recent video for the song “Born Free”, which features what appears to be an American SWAT team hunting down and killing red-headed males. Politically, it’s completely obtuse, but it is pretty much what happens when the need to be seen as “radical” overwhelms all other artistic considerations.