Indeed, and I've pretty much done it. But it takes effort. You need credible replacements for the mindless time, and then you need to actively push yourself towards the new stuff as opposed to the old stuff.
The credible replacements is everything. If you commute by car, you need either:
-Some audiotapes/audiobooks/podcasts
-Someone to carpool with
-Some way of not driving any more (car service if you're wealthy enough, taking the train or bus otherwise)
...otherwise you're going to listen to the radio. What else is there to do while driving?
So it takes some effort. Totally doable though. I just calculated out how much time I spent on pop culture this year - Only one movie (Robin Hood, meh - I would've seen Inception except I was in the back provinces of China when it was released, and then it was gone from theaters when I was back in civilization), less than ten hours of TV (mostly tennis), no pop music except what was on when I was wandering through stores playing music or at a bar, no newspapers, and a few hours of trashy magazines while sitting in an aeronautical engineer friend's bathroom (why he reads them is beyond me, but it wasn't a terrible use of time while in his bathroom).
But this is only possible because I've got a list of stuff to do - a Kindle loaded with good books, an mp3 player loaded with audiobooks/podcasts, Hacker News/LessWrong/Google Reader loaded with good blogs, Lichess.org for when I want to play a game of Chess, and a list of temples/mosques/ruins/parks/beaches to go to.
It's not enough to just "opt out" - you need to "opt in" to some comparable activity to fill your time.
