Well, durr.
The majority of P2P traffic is media content. When people want to consume media content on their own schedule, on whatever device they have, without having ads thrust in their face mid-program, they find a way.
For many, this way is bit torrent. For many others, it's iTunes/Netflix - often the difference in choice is the convenience or availability, sometimes it's the price. Some people will watch a few ads for cheaper content (I presume the Hulu vs. Netflix people?) - some will pay more for additional device convenience (I see this as the iTunes people).
Unfortunately, some entire markets have none of these options available; or with unreasonable compromises in the other criteria. In Australia, Hulu is blocked completely, Netflix plans are more expensive for less selection, and iTunes is more expensive still for less selection and often months behind US releases. All our Internet plans have limited monthly traffic quotas, and most major ISPs only partner with one (if any) of the above for un-metered content.
Hypothetically - say that I have money to spend on home entertainment. With P2P, I could pick a show I like from a list of RSS feeds and have every episode downloaded into a folder as its released, or scheduled for overnight (off-peak quota) download. Once I had the file, I could play it on the TV, PC, laptop, or iPod as easily as any of the commercial options (sans iTunes->iPod option, which would involve a HandBrake step). I could watch it as many times as I want. I could show it to my friends. I could download it again if I didn't want to use the drive space to keep it around.
Take my money - give me the product you have the way I want it, or I'll get it from somewhere else.