There are many reasons why technology advances are making people interact with each other less and less. It's very simple to log onto any social media and contact a friend for free. While if you drive to meet a friend you would waste gas and time. Technology makes everything simpler. From texting a family member to even buying groceries! Technology is making humans less social because why would people waste time and energy on going out while they can just watch a movie on their phone? Everybody prefers the way solution. And unfortunately the easy solution is just staying at home and watching television or surfing the web.
Krakauer won't get to those details until near the end of the book. Secondly, by starting at the end of the story, Krakauer is indicating that this book will be centrally concerned with exploring Chris's death. The facts of his life will be important insofar as they provide an explanation for how it ended.