Dang. I knew I shouldn't have made fun of those cave people. I've tried running this giant wool sock through the washer twice, and all I've got to show for it is a somewhat cleaner giant wool sock.
Man, after felting that boot I realized why felt was the first form of fabric. It was so simple. Even a cave-person could throw their boot in the washing machine and forget it was there for half an hour. They were probably too stupid to knit, though. Ha ha, stupid cave people.