It's difficult - on the one hand you have the fact that people go to concerts because they've heard of stuff (hence why Beethoven's symphonies are always performed), but on the other hand people see that and don't find it terribly exciting outside of an educational experience. If there was a performance of a new composer's work that nobody had heard of, would people rush to go see it? Outside of people who already like classical music, I don't believe so. Though the LA Phil is modernizing to some success. For me it was all about having some knowledge behind the music. You listen to Berlioz's requiem, and you're like alright I guess this is cool, but when you can imagine the skies opening up and the brass coming in when the angels descend on earth because you know that's what it's about, you get the chilly willies. In another example outside of more program related music, there is Bach or the late string quartets of Beethoven - these pieces that are so amazingly technical, that you really need to pay attention to where each note is leading and how it bends your expectations every single time. Otherwise you might just hear the baroque cadences that everyone knows over and over again and become bored. Also, I'd friggin love it if some of the absolutely huge performances like Mahler's symphony of a Thousand or Berlioz etc. would be performed with the actual amount of musicians that they wanted. I understand that this would be difficult and costly, but that would really knock even the casual person off their feet if there were a thousand musicians playing at once rather than just the four or five through amps that we're used to.