Authenticity is a terrible term by which to judge art. It’s thrown around a lot! I.E., this guy did heroin and killed their friend at the train tracks, ergo his book is good. This guy went to juke joints for six months (leaving because he had no money/was scared) so ergo, his blues are better than yours.
Authenticity is a straw-man, an initial feint coming from an artist (often) with a background of super-privilege or, alternately, super-in-the-muck. The real question, I think, when it comes to art (whatever it may be): does it move me? Is there blood* behind it, pulsing through it? Is there more on its mind than sheer entertainment? (And while that may have its value, of course, perhaps that’s the difference between a momentary diversion and something Great, something that shifts the molecules a little bit, makes you look at the world through new eyes.)
That kind of experience is a rush, a kick, a high. Exhilarating. And you could argue that art is quite possibly the easiest route to that sort of human experience.
* Semi-related, but in the “how to be a great English major” files: make sure every term paper you write is about sex. Look for the seething, raging sexuality underneath whatever Lake Placid the book may offer. It will make your writing better, give it a drive. You will get an A.