Disney World is run by rival adhocracies, each dedicated to providing the best experience to the park's visitors and competing for the Whuffie the guests offer.
Julius finally "cracks" when he sees his dreams turned to dust and he bashes up the attractions in the Hall of Presidents, in the process also damaging his own cranial interface to the point that he can no longer back himself up.
Dan leaves Lil, Julius is kicked out of the ad hoc and his Whuffie hits rock bottom — low enough that others take his possessions with impunity and elevators don't stop for him.
The book is his attempt to manually document the happenings of the previous year so that, when this incarnation is eventually killed by age or accident, his restored backup will have a partial record of the transpiring events.
Dan decides not to take a lethal injection, but to deadhead (putting oneself into a voluntary coma) till the heat death of the Universe.
[1][2][3] Cory Doctorow said "Down and Out in the Magic Kingdom was the first novel released under a Creative Commons license, and I've spent the past four years exhorting fans to copy my work and share it.