I don't understand what the dated aspect has to do with it. Everything becomes dated. If you think about it, Chicago is dated because it's not the 1920's and there is no prohibition. People can buy alcohol now, but does that stop them from seeing Chicago? But greed, fame, murder, media, etc are all still very relevant. From RENT, AZT and the East Village are both dated (how they are portrayed). But love, survival, death, friendship, etc are all still very relevant. The fact that the East Village is different now is not going to stop anyone from seeing a show. See? Both shows have their dated aspects. I don't see why that's holding RENT back. What Aigoo said, though, the fact that it draws a more specific audience. I could see that being much more of a detriment than the "dated" aspect.
"This table, he is over one hundred years old. If I could, I would take an old gramophone needle and run it along the surface of the wood. To hear the music of the voices. All that was said." - Doug Wright, I Am My Own Wife