This is something I have been debating many times, as I got friend who always "just" look for new stuff to consume and very rarely look back to the old.
First of all I have to say, something that I didnt really accept until like a year or two ago; Play what you want to play.
I believe that going back to a game, film or book that you already gone through can be a lot of fun. You might discover new details, get a better understanding of story or just get a bunch of enjoyable hours. Its like revisiting places you've been before, you now got a emotional connection and in my opinion it can enhance the experience.
Its nothing wrong to consume new media, but there is so much so you wont have time to catch anyway. Also, I almost feel as if its hard to appreciate something if you dont go back and maybe reflect on something instead of just go "thank you next".