Interesting post. I'm adding my comments here because white text on black background is physically painful to me!
What's interesting is how you make your point with movies like Star Wars and bands like Nirvana and Sonic Youth... when the reason those movies and bands reached their popularity (and made their money) was due to being picked up by media producers that were already in the "system" that is criticized as being stuck in an old or non-innovative direction. Would Star Wars have done as well if 20th Century Fox hadn't picked them up? Suppose it had been Republic Pictures, for instance, and the resulting significantly lower budget had created a very different (and less impressive-looking) movie? Suppose none of them picked it up, and Lucas made the movie in his basement?
Your examples seem less about the quality of the "new-direction" artists, and more about the ability of Big Media to occasionally pick an unexpected winner out of the indie throngs. And it doesn't address the indies that don't get that opportunity: For every Kevin Smith that finally got noticed, there are a hundred artists who have produced an entire movie on a single Sony Handcam, mortgaging themselves to the hilt in the process, and worked like hell to promote that work in local film festivals, on the web and at local community colleges and art houses. They haven't been picked up by Big Media... they won't make it to Cannes... should we assume, then, that they all suck?
Although we should all look for the "undiscovered gold" being produced out there, we need to look past the tidbits that Big Media will obligingly find (and profit from) for us. Fortunately, the web is providing us ways to find our gold by ourselves, whether Big Media finds it or not.