Because the point of reading the book is not to exactly replicate his life. Only to be aware of ways of reducing the amount of work in your own life.

Edit: it's the same idea as when I boxed competitively, and watched a Manny Pacquiao documentary. I wasn't going to wake up at 3 am to drink a 1000 calorie shake or do a 1000 sit ups everyday. I wanted to get into the mindset of optimizing my training within the reasonable constraints of my student life.