Yeah, pre-race they talked a lot about how he was dealing with his sick daughter, and only started putting in more miles in the summer, so he'll be "more fresh." Sounded to me like he was missing a very important component of his base.
No, it's because the marathon is an utterly unpredictable event and the training build-up often has little to do with the actual performance.
Run a 5k. The range of performances from great to terrible is much smaller.
Why do people put all of their eggs in two baskets per year and blow up half of the time? MARATHONS ARE SO DUMB.