Because they can.
Bingo. I myself have always been a member of that "just because I CAN do something doesn't necessarily mean that I WILL do it" camp. Since I find it hard to shave without looking at myself in a mirror to get the nooks and crannies, I guess I'll just keep writing checks when it comes to filling up my hard drive with music.
Did you know that the only individuals the RIAA has pursued legally are those that allow uploading from their hard drive?
If I ever download a piece of music that I would have bought, I will send a check. For example, I have downloaded several videos from Pink Floyd's Pulse. I have alse checked the video store every month for two years for dvd availability. I also used to own it on laserdisc before it got thrown in the trash over a divorce.
I feel no guilt downloading any of those videos or the mp3's. None whatsoever.