“Your ISP is already required to monitor you and keeps logs X number on behalf of the government or any person who wants to serve them with a subpeona.”
There is no law that requires ISPs to keep logs for any certain length of time. They are only required to monitor a specific user after they are served with a subpoena, as is required of the phone companies under wiretap laws.
Most ISPs keep logs for maintenance purposes and dump the logs periodically. It used to be they would keep the data for about a month, I don’t know what it is now.
I’ve never quite understood the difference between acquiring a free mp3 and acquiring a CD free from the public library. Chances are both will be listened to for the same period of time before deletion/return.