You only read the stories written by pilots who are good story tellers; nobody shares the rest.

Because they tend to have big egos (even fighter pilots will admit that ;-) and spend a lot of time telling flying stories.

Practice! All they ever do in the bar is tell flying stories...

Nice catch! I think they practice in bars

Besides the obvious selection/survivor bias of good stories. It's likely that if anyone of a population (like say the airforce) is going to have good story telling it's going to be the ones that are the best out of that population in applying themselves (like jet fighter pilots). E.g. I doubt it's that they are good story tellers, I would bet that it's that they are just good at anything they do through applying themselves.