A critisism of the OSR that I often see is that it is conservative. This seems self-evident, and even members of the OSR themselves don't really make an effort to dispute it. Going back to an older way of doing things. Playing earlier versions of the game. Conservative, right?
Well, not necesseraly. The OSR, as I see it, goes back to the roots of the game, trying to discover the ideas behind the original concept - ideas that were lost because people didn't understand them or weren't exposed to them - and then developing them in a new direction. Many of the theoretical concepts I see differ quite a bit from what the 1e DMG proposes.
I won't go into that in detail, but there are other examples of this same phenomenon in other art forms as well. Many times you see the artists deemed to be the most original claim outdated artists as their idols. In fact, looking backwards in history allows you to see past the shackles of contemporary trends and find a truer meaning behind the thing you do. Think about this the next time you hear your favorite musician talk about who (s)he is inspired by.
In the OSR, this is all about finding out how the game was intended to be played, and then finding new ways to make that play happen.