For the most part, I would say the reason why is that the trailer did not really appeal to me. Movies that appeal the most to me in trailers have to be mysterious in a sense. Take for example the trailer for the movie Super 8. You did not know what it was about but it was extremely intriguing. The trailer for Joker seemed as if it was something that is commonly covered. Hollywood these days seem to really love covering origin stories of characters in existing media.