It’s not only about having the availability but also about the price. Now we have Spotify here and it’s awesome and a lot of folks don’t even think about pirating — they can stream for free from Spotify and Youtube and Vbox7. I wonder how many pay for Spotify though (I’m one of them). Then we get to the next thing — Netflix and other on demand services. They are cool and have some interesting shows and documentaries but the service is still not good enough for most people to switch to it (lack of subtitles or dubbed audio, the content is better than launch day but still not really good enough) and not cheap enough (though Idoubt ad revenue could allow it even to go as cheap as free). HBO Go is sort of an alternative … if you’re already paying for cable on top of your internet bill.
This web comic illustrates the point further. http://theoatmeal.com/comics/game_of_thrones
One day the piracy will decrease but before this happens there must be convenience at an affordable price. Until then you won’t be able to push the torrent trackers out of top100 most visited sites according to Alexa (even top10 would be a struggle at the moment).