I don't think the YouTube Symphony Orchestra will have an impact on the role of concert music in American culture, or even a substantial impact on the concert music industry. In a nutshell, the novelty of the project was how the orchestra was chosen, but the concert experience that resulted was quite traditional. Yes, there were some nifty visuals, and some new music, but the audience was still expected to sit passively in America's musical temple (while the ushers fought a never-ending battle with those bold enough to take photographs of their loved ones on stage, apparently).
I can't help but feel that the project's organizers missed a golden opportunity to redefine the 21st-century concert experience. If you're going to subvert the orchestra audition process, why not subvert the whole production from beginning to end?