Why an average rating?

I am 60 years, recently retired, I have a taste for travel, I'm athletic, I would like to make trips on foot or by bike independently, so I was impressed during a visit to the author of the TV.
The review of ten years of retirement with the initial difficulties and extraordinary journeys made, have led me to buy the book, I read it in two days and with great pleasure.
However, after the end, I felt a little frustrated because the words are a bit redundant (felt by the author), it deserved a broadening of scientific research (psychological ...) at the experiences of other people even briefly to put into perspective the story of an exciting human adventure.