This may not be an especially profound insight, but the thing I notice most about artists who are most successful in terms of putting a personal stamp on their work is that they are that much more in touch with what they are. That person may be of one given political bent or another; they may be meek or bold; they may be tough or sensitive. But whatever it is, they are entirely cognizant of it and in tune with it. They know how to look inside themselves to get whatever it is they need to speak their mind. They don't need anyone else's work to serve as a model. Inspiration or perspective, maybe, but nothing more than that.
As my friend Steven put it, "Their writing is being them, and at least they're them." I agreed: it's self-expression — not in the sense of "look at me", but rather "look at how I see this; see this through my eyes as only I know how". But so many people — writers, and readers alike — are willing to settle for borrowed vision.
Most people are willing to settle because we're not in the habit of thinking about our entertainments as anything but. We didn't think twice about the lousy food we ate until obesity and diabetes started skyrocketing, and then allasudden we realized we'd aided and abetted a system that made it more expensive to buy (or prepare) a salad than grab a hamburger.
Likewise, we've done the same things with our entertainments. We've given precedence and preferential treatment to things that are not good for us, not even on the level of mindless fun, and then we wonder why everything is a vague (or not-so-vague) echo of everything else. It isn't just that we've starved audiences, but that we've starved the current and future generations of creators as well, and given them no incentive to think about what else might be possible. The eyes we give creators to look through aren't even their own anymore — they're a composite of everyone else's.